Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Hepatology ; 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32080887

RESUMO

Forkhead box M1 (FOXM1) and NF-ĸB are oncogenic drivers in liver cancer that positively regulate each other. We showed that methionine adenosyltransferase 1A (MAT1A) is a tumor suppressor in the liver and it inhibits NF-ĸB activity. Here we examined the interplay between FOXM1/NF-kB and MAT1A in liver cancer. We examined gene and protein expression, effects on promoter activities and binding of proteins to promoter regions, effects of FOXM1 inhibitors T0901317 (T0) and FDI-6 in vitro and in xenograft and syngeneic models of liver cancer. We found in both hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) an induction in FOXM1 and NF-κB expression is accompanied by fall in MATα1 (protein encoded by MAT1A). The TCGA dataset confirmed the inverse correlation between FOXM1 and MAT1A. Interestingly, FOXM1 directly interact with MATα1 and they negatively regulate each other. In contrast, FOXM1 positively regulates p50 and p65 expression via MATα1, as the effect is lost in its absence. FOXM1, MATα1 and NF-κB all bind to the FOX-binding sites in the FOXM1 and MAT1A promoters. However, binding of FOXM1 and NF-κB repressed MAT1A promoter activity but activated FOXM1 promoter. In contrast, binding of MATα1 repressed FOXM1 promoter. MATα1 also binds and represses the NF-κB element in the presence of p65 or p50. Inhibiting FOXM1 with either T0 or FDI-6 inhibited liver cancer cell growth in vitro and in vivo. However, inhibiting FOXM1 had minimal effects in liver cancer cells that do not express MAT1A. CONCLUSION: We have unveiled a novel crosstalk between FOXM1/NF-κB and MAT1A. Upregulation in FOXM1 lowers MAT1A but raises NF-κB expression and this is a feed forward loop that enhances tumorigenesis.

2.
Zool Res ; 41(1): 32-38, 2020 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-31709783

RESUMO

Previous studies have revealed faster detection of snake images in humans and non-human primates (NHPs), suggesting automatic detection of evolutionary fear-relevant stimuli. Furthermore, human studies have indicated that general fear-relevance rather than evolutionary relevance is more effective at capturing attention. However, the issue remains unclarified in NHPs. Thus, in the present study, we explored the attentional features of laboratory-reared monkeys to evolutionary and general fear-relevant stimuli (e.g., images of snakes, capturing gloves). Eye-tracking technology was utilized to assess attentional features as it can provide more accurate latency and variables of viewing duration and frequency compared with visual search task (VST) and response latency adopted in previous studies. In addition, those with autism spectrum disorder (ASD) show abnormal attention to threatening stimuli, including snake images. Rett syndrome (RTT) is considered a subcategory of ASD due to the display of autistic features. However, the attentional features of RTT patients or animal models to such stimuli remain unclear. Therefore, we also investigated the issue in MECP2 gene-edited RTT monkeys. The influence of different cognitive loads on attention was further explored by presenting one, two, or four images to increase stimulus complexity. The eye-tracking results revealed no significant differences between RTT and control monkeys, who all presented increased viewing (duration and frequency) of snake images but not of aversive stimuli compared with control images, thus suggesting attentional preference for evolutionary rather than general fear-relevant visual stimuli. Moreover, the preference was only revealed in visual tasks composed of two or four images, suggesting its cognitive-load dependency.


Assuntos
Atenção/fisiologia , Movimentos Oculares/fisiologia , Macaca fascicularis/fisiologia , Serpentes , Animais , Evolução Biológica , Medições dos Movimentos Oculares , Medo , Feminino , Macaca fascicularis/genética , Proteína 2 de Ligação a Metil-CpG/genética
3.
Appl Environ Microbiol ; 85(24)2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31604771

RESUMO

Many Gram-negative bacteria employ N-acylhomoserine lactones (AHLs) as quorum-sensing (QS) signal molecules to regulate virulence expression in a density-dependent manner. Quorum quenching (QQ) via enzymatic inactivation of AHLs is a promising strategy to reduce bacterial infections and drug resistance. Herein, a thermostable AHL lactonase (AidB), which could degrade different AHLs, with or without a substitution of carbonyl or hydroxyl at the C-3 position, was identified from the soil bacterium Bosea sp. strain F3-2. Ultrahigh-performance liquid chromatography analysis demonstrated that AidB is an AHL lactonase that hydrolyzes the ester bond of the homoserine lactone (HSL) ring. AidB was thermostable in the range 30 to 80°C and showed maximum activity after preincubation at 60°C for 30 min. The optimum temperature of AidB was 60°C, and the enzyme could be stably stored in double-distilled water (ddH2O) at 4°C or room temperature. AidB homologs were found only in Rhizobiales and Rhodospirillales of the Alphaproteobacteria AidB from Agrobacterium tumefaciens and AidB from Rhizobium multihospitium (with amino acid identities of 50.6% and 52.8% to AidB, respectively) also showed thermostable AHL degradation activity. When introduced into bacteria, plasmid-expressed AidB attenuated pyocyanin production by Pseudomonas aeruginosa PAO1 and the pathogenicity of Pectobacterium carotovorum subsp. carotovorum Z3-3, suggesting that AidB is a potential therapeutic agent by degrading AHLs.IMPORTANCE A quorum-sensing system using AHLs as the signal in many bacterial pathogens is a critical virulence regulator and an attractive target for anti-infective drugs. In this work, we identified a novel AHL lactonase, AidB, from a soil bacterial strain, Bosea sp. F3-2. The expression of aidB reduced the production of AHL signals and QS-dependent virulence factors in Pseudomonas aeruginosa and Pectobacterium carotovorum The homologs of AidB with AHL-degrading activities were found only in several genera belonging to the Alphaproteobacteria Remarkably, AidB is a thermostable enzyme that retained its catalytic activity after treatment at 80°C for 30 min and exhibits reliable storage stability at both 4°C and room temperature. These properties might make it more suitable for practical application.

4.
Front Plant Sci ; 10: 1059, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31543889

RESUMO

The type III secretion system (T3SS) in many Gram-negative bacterial pathogens is regarded as the most critical virulence determinant and an attractive target for novel anti-virulence drugs. In this study, we constructed a T3SS secretion reporter containing the ß-lactamase gene fused with a signal peptide sequence of the T3SS effector gene, and established a high-throughput screening system for T3SS inhibitors in the plant pathogenic bacterium Acidovorax citrulli. From a library of 12,000 chemical compounds, we identified a series of benzyloxy carbonimidoyl dicyanide (BCD) derivatives that effectively blocked T3SS-dependent ß-lactamase secretion. Substitution of halogens or nitro groups at the para-position on the benzene ring contributed to an increased inhibitory activity. One representative compound, BCD03 (3,4-dichloro-benzyloxy carbonimidoyl dicyanide), dramatically reduced pathogenicity of A. citrulli on melon seedlings, and attenuated hypersensitive responses in the non-host Nicotiana tabacum caused by pathogenic bacteria A. citrulli, Xanthomonas oryzae pv. oryzae and Pseudomonas syringae pv. tomato at sub-MIC concentrations. Western blotting assay further confirmed that BCD03 inhibited effector secretion from the above bacteria via T3SS in the liquid medium. Taken together, our data suggest that BCD derivatives act as novel inhibitors of T3SS in multiple plant bacterial pathogens.

5.
Commun Biol ; 2: 274, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31372513

RESUMO

Natural polysaccharides have received much attention for their ability to ameliorate hepatic steatosis induced by high-fat diet. However, the potential risks of their use have been less investigated. Here, we show that the exopolysaccharides (EPS) from Lactobacillus rhamnosus GG (LGG) and L. casei BL23 reduce hepatic steatosis in zebrafish fed a high-fat diet, while BL23 EPS, but not LGG EPS, induce liver inflammation and injury. This is due to the fact that BL23 EPS induces gut microbial dysbiosis, while LGG EPS promotes microbial homeostasis. We find that LGG EPS, but not BL23 EPS, can directly activate intestinal HIF1α, and increased HIF1α boosts local antimicrobial peptide expression to facilitate microbial homeostasis, explaining the distinct compositions of LGG EPS- and BL23 EPS-associated microbiota. Finally, we find that liver injury risk is not confined to Lactobacillus-derived EPS but extends to other types of commonly used natural polysaccharides, depending on their HIF1α activation efficiency.

6.
Environ Pollut ; 252(Pt A): 888-896, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31207573

RESUMO

In this study, we develop a new composite material of Fe-Cu/D407 composite via using nanoscale zero-valent iron (nZVI) with copper deposited on chelating resin (D407) to remove nitrate from the water. The experimental results show that a remarkable nitrate removal and the selectivity of N2 are 99.9% and 89.7%, respectively, under the anaerobic conditions of Cu/Fe molar ratio of 1:2, pH = 3.0. Even without of inert gas and adjusting the initial pH of the solution, the removal rate of nitrate by Fe-Cu/D407 reached to 85% and the selectivity of nitrogen reached to 55%. Meanwhile, the Fe-Cu/D407 maintained preferable removal efficiency of nitrate (100% - 92%) over a wide pH range of 3-11. In addition, the removal rate of the drinking water, lake water and wastewater from the Fe-Cu/D407 is still very high and the reactivity of Fe-Cu/D407 was relatively unaffected by the presence of dissolved ions in the waters tested. Moreover, the synergetic effect of Fe, Cu and D407 in the composite Fe-Cu/D407 were well investigated for the first time according to the analyses of TPR, XPS and EIS. The catalytic mechanism and denitrification routes were also proposed.


Assuntos
Cobre/química , Ferro/química , Nitratos/análise , Óxidos de Nitrogênio/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Catálise , Desnitrificação , Recuperação e Remediação Ambiental/métodos , Nitrogênio/análise , Águas Residuárias/química
7.
Acta Pharmacol Sin ; 39(10): 1590-1603, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29620051

RESUMO

Induced pluripotent stem cell (iPSC)-based cardiac regenerative medicine requires the efficient generation, structural soundness and proper functioning of mature cardiomyocytes, derived from the patient's somatic cells. The most important functional property of cardiomyocytes is the ability to contract. Currently available methods routinely used to test and quantify cardiomyocyte function involve techniques that are labor-intensive, invasive, require sophisticated instruments or can adversely affect cell vitality. We recently developed optical flow imaging method analyses and quantified cardiomyocyte contractile kinetics from video microscopic recordings without compromising cell quality. Specifically, our automated particle image velocimetry (PIV) analysis of phase-contrast video images captured at a high frame rate yields statistical measures characterizing the beating frequency, amplitude, average waveform and beat-to-beat variations. Thus, it can be a powerful assessment tool to monitor cardiomyocyte quality and maturity. Here we demonstrate the ability of our analysis to characterize the chronotropic responses of human iPSC-derived cardiomyocytes to a panel of ion channel modulators and also to doxorubicin, a chemotherapy agent with known cardiotoxic side effects. We conclude that the PIV-derived beat patterns can identify the elongation or shortening of specific phases in the contractility cycle, and the obtained chronotropic responses are in accord with known clinical outcomes. Hence, this system can serve as a powerful tool to screen the new and currently available pharmacological compounds for cardiotoxic effects.


Assuntos
Cardiotoxicidade/diagnóstico , Fármacos Cardiovasculares/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Frequência Cardíaca/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Células Cultivadas , Doxorrubicina/efeitos adversos , Doxorrubicina/farmacologia , Citometria de Fluxo/métodos , Humanos , Células-Tronco Pluripotentes Induzidas/fisiologia , Modelos Biológicos , Miócitos Cardíacos/fisiologia
8.
World J Emerg Med ; 9(2): 118-124, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29576824

RESUMO

BACKGROUND: Data on the mechanical ventilation (MV) characteristics and radiologic features for the cases with H7N9-induced ARDS were still lacking. METHODS: We describe the MV characteristics and radiologic features of adult patients with ARDS due to microbiologically confirmed H7N9 admitted to our ICU over a 3-month period. RESULTS: Eight patients (mean age 57.38±16.75; 5 male) were diagnosed with H7N9 in the first quarter of 2014. All developed respiratory failure complicated by acute respiratory distress syndrome (ARDS), which required MV in ICU. The baseline APACHE II and SOFA score was 11.77±6.32 and 7.71±3.12. The overall CT scores of the patients was 247.68±34.28 and the range of CT scores was 196.3-294.7. The average MV days was 14.63±6.14, and 4 patients required additional rescue therapies for refractory hypoxemia. Despite these measures, 3 patients died. CONCLUSION: In H7N9-infected patients with ARDS, low tidal volume strategy was the conventional mode. RM as one of rescue therapies to refractory hypoxemia in these patients with serious architectural distortion and high CT scores, which could cause further lung damage, may induce bad outcomes and requires serious consideration. Prone ventilation may improve mortality, and should be performed at the early stage of the disease, not as a rescue therapy.

9.
Appl Biochem Biotechnol ; 185(4): 1100-1117, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29453614

RESUMO

Isochrysis is a genus of marine algae without cell wall and capable of accumulating lipids. In this study, the lipid production potential of Isochrysis was assessed by comparing 15 Isochrysis strains with respect to their growth rate, lipid production, and fatty acid profiles. Three best strains were selected (lipid productivity, 103.0~121.7 mg L-1 day-1) and their lipid-producing capacities were further examined under different controlled parameters, e.g., growth phase, medium nutrient, and light intensity in laboratory cultures. Furthermore, the three Isochrysis strains were monitored in outdoor panel photobioreactors with various initial cell densities and optical paths, and the strain CS177 demonstrated the superior potential for outdoor cultivation. A two-stage semi-continuous strategy for CS177 was subsequently developed, where high productivities of biomass (1.1 g L-1 day-1) and lipid (0.35 g L-1 day-1) were achieved. This is a comprehensive study to evaluate the lipid-producing capability of Isochrysis strains under both indoor and outdoor conditions. Results of the present work lay a solid foundation for the physiological and biochemical responses of Isochrysis to various conditions, shedding light on the future utilization of this cell wall-lacking marine alga for biofuel production.


Assuntos
Biomassa , Haptófitas/crescimento & desenvolvimento , Lipídeos/biossíntese , Haptófitas/genética , Lipídeos/genética
10.
Appl Biochem Biotechnol ; 184(2): 524-537, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28762006

RESUMO

Producing biodiesel from microalgae grown in wastewater is environment-friendly and cost-effective. The present study investigated the algae found in wastewater of a local dairy farm for their potential as biodiesel feedstocks. Thirteen native algal strains were isolated. On the basis of morphology and 16S/18S rRNA gene sequences, one strain was identified to be a member of cyanobacteria, while other 12 strains belong to green algae. After screening, two Scenedesmus strains out of the 13 microalgae isolates demonstrated superiority in growth rate, lipid productivity, and sedimentation properties, and therefore were selected for further scale-up outdoor cultivation. Both Scenedesmus strains quickly adapted to the outdoor conditions, exhibiting reasonably good growth and strong anti-contamination capabilities. In flat-plate photobioreactors (PBRs), algal cells accumulated predominantly neutral lipids that accounted for over 60% of total lipids with almost 70% being triacylglycerol. In addition, Scenedesmus obliquus had a high content of monounsaturated fatty acids, of which the amount of oleic acid (C18:1) was up to 27.11%. Based on these findings, the dairy farm wastewater-isolated Scenedesmus strains represent promising sources of low-cost, high-quality oil for biofuel production.


Assuntos
Biocombustíveis , Reatores Biológicos , Ácidos Graxos/biossíntese , Microalgas/crescimento & desenvolvimento , Scenedesmus/crescimento & desenvolvimento , Águas Residuárias , Purificação da Água/métodos
11.
Sci Rep ; 7(1): 16291, 2017 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-29176648

RESUMO

To understand why most eukaryotic microalgae accumulate lipids during nitrogen starvation stress, a gene, MiglnB, encoding PII, a signal transduction protein, was cloned from the arachidonic acid-rich microalga Myrmecia incisa Reisigl. Similarly to its homologues, MiPII contains three conserved T-, B-, and C-loops. In the presence of abundant Mg2+, ATP, and Gln, MiPII upregulates Arg biosynthesis by interacting with the rate-limiting enzyme, MiNAGK, as evidenced by yeast two-hybrid, co-immunoprecipitation assays, and kinetics analysis of enzyme-catalyzed reactions. However, this interaction of MiPII with MiNAGK is reversed by addition of 2-oxoglutarate (2-OG). Moreover, this interaction is present in the chloroplasts of M. incisa, as illustrated cytologically by both immunoelectron microscopy and agroinfiltration of Nicotiana benthamiana leaves to determine the subcellular localization of MiPII with MiNAGK. During the process of nitrogen starvation, soluble Arg levels in M. incisa are modulated by a change in MiNAGK enzymatic activity, both of which are significantly correlated (r = 0.854). A model for the manipulation of Arg biosynthesis via MiPII in M. incisa chloroplasts in response to nitrogen starvation is proposed. The ATP and 2-OG saved from Arg biosynthesis is thus suggested to facilitate the accumulation of fatty acids and triacylglycerol in M. incisa during exposure to nitrogen starvation.


Assuntos
Microalgas/metabolismo , Nitrogênio/metabolismo , Trifosfato de Adenosina/metabolismo , Magnésio/metabolismo , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
12.
Neural Regen Res ; 12(8): 1365-1374, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28966654

RESUMO

Non-traumatic injury accounts for approximately half of clinical spinal cord injury, including chronic spinal cord compression. However, previous rodent spinal cord compression models are mainly designed for rats, few are available for mice. Our aim is to develop a thoracic progressive compression mice model of spinal cord injury. In this study, adult wild-type C57BL/6 mice were divided into two groups: in the surgery group, a screw was inserted at T9 lamina to compress the spinal cord, and the compression was increased by turning it further into the canal (0.2 mm) post-surgery every 2 weeks up to 8 weeks. In the control group, a hole was drilled into the lamina without inserting a screw. The results showed that Basso Mouse Scale scores were lower and gait worsened. In addition, the degree of hindlimb dysfunction in mice was consistent with the degree of spinal cord compression. The number of motor neurons in the anterior horn of the spinal cord was reduced in all groups of mice, whereas astrocytes and microglia were gradually activated and proliferated. In conclusion, this progressive compression of thoracic spinal cord injury in mice is a preferable model for chronic progressive spinal cord compression injury.

13.
J Phycol ; 53(1): 235-240, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27885670

RESUMO

Telomeres generally consist of short repeats of minisatellite DNA sequences and are useful in chromosome identification and karyotype analysis. To date, telomeres have not been characterized in the economically important brown seaweed Saccharina japonica, thus its full cytogenetic research and genetic breeding potential has not been realized. Herein, the tentative sequence of telomeres in S. japonica was identified by PCR amplification with primers designed based on the Arabidopsis-type telomere sequence (TTTAGGG)n , which was chosen out of three possible telomeric repeat DNA sequences typically present in plants and algae. After PCR optimization and cloning, sequence analysis of the amplified products from S. japonica genomic DNA showed that they were composed of repeat units, (TTTAGGG)n , in which the repeat number ranged from 15 to 63 (n = 46). This type of repeat sequence was verified by a Southern blot assay with the Arabidopsis-type telomere sequence as a probe. The digestion of S. japonica genomic DNA with the exonuclease Bal31 illustrated that the target sequence corresponding to the Arabidopsis-type telomere sequence was susceptible to Bal31 digestion, suggesting that the repeat sequence was likely located at the outermost ends of the kelp chromosomes. Fluorescence in situ hybridizations with the aforementioned probe provided the initial cytogenetic evidence that the hybridization signals were principally localized at both ends of S. japonica chromosomes. This study indicates that the telomeric repeat of the kelp chromosomes is (TTTAGGG)n which differs from the previously reported (TTAGGG)n sequence in Ectocarpus siliculosus through genome sequencing, thereby suggesting distinct telomeres in brown seaweeds.


Assuntos
Feófitas/genética , Sequências Repetitivas de Ácido Nucleico , Telômero , Southern Blotting , Hibridização in Situ Fluorescente , Laminaria/genética
14.
Nan Fang Yi Ke Da Xue Xue Bao ; 36(12): 1727-1731, 2016 Dec 20.
Artigo em Chinês | MEDLINE | ID: mdl-27998873

RESUMO

OBJECTIVE: To investigate the involvement of PI3K/Akt signaling pathway in the changes of urine protein in adriamycin-induced nephropathic rats treated with dexamethasone and LY294002 (a PI3K inhibitor). METHODS: SD rats were randomized into normal control group, ariamycin-induced nephropathy group (ADR group), ariamycin+dexamethasone group (DEX group), and ADR+DEX+LY294002 group (LY294002 group). On days 7, 14 and 28 after the treatments, 24-h urine was collected from the rats to analyze the total urine proteins. The renal tissues were obtained on day 28 to examine the expressions of p-AKT, AKT and Bad proteins in the cortical tissues using Western blotting; the expression of Bad mRNA in the cortical tissues was measured by QPCR. RESULTS: Urine protein increased progressively in ADR group accompanied by significantly reduced p-AKT/AKT ratio and increased Bad mRNA expression in comparison with those in the normal control group (P<0.05). Urine protein was obviously reduced in DEX group with comparable p-AKT/AKT ratio and Bad mRNA expression level with those in the control group (P>0.05). Urine protein showed no significant reduction in LY294002 group, but the p-AKT/AKT ratio was significantly reduced and Bad mRNA expression was increased compared with those in DEX group (P<0.05). CONCLUSION: Dexamethasone increases the expression of Bad mRNA and reduces urine protein in adriamycin-induced nephropathic rats by activating PI3K/Akt signaling pathway. LY294002 can inhibit PI3K/Akt signaling pathway to block the effect of dexamethasone, suggesting that PI3K/Akt signaling pathway is one of the signaling pathways that mediate the effect of dexamethasone on proteinuria.


Assuntos
Anti-Inflamatórios/farmacologia , Cromonas/farmacologia , Dexametasona/farmacologia , Morfolinas/farmacologia , Fosfatidilinositol 3-Quinases/fisiologia , Proteinúria , Proteínas Proto-Oncogênicas c-akt , Animais , RNA Mensageiro , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Transdução de Sinais , Proteína de Morte Celular Associada a bcl
15.
Int J Mol Sci ; 17(7)2016 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-27438826

RESUMO

The green alga Myrmecia incisa is one of the richest natural sources of arachidonic acid (ArA). To better understand the regulation of ArA biosynthesis in M. incisa, a novel gene putatively encoding the Δ9 fatty acid desaturase (FAD) was cloned and characterized for the first time. Rapid-amplification of cDNA ends (RACE) was employed to yield a full length cDNA designated as MiΔ9FAD, which is 2442 bp long in sequence. Comparing cDNA open reading frame (ORF) sequence to genomic sequence indicated that there are 8 introns interrupting the coding region. The deduced MiΔ9FAD protein is composed of 432 amino acids. It is soluble and localized in the chloroplast, as evidenced by the absence of transmembrane domains as well as the presence of a 61-amino acid chloroplast transit peptide. Multiple sequence alignment of amino acids revealed two conserved histidine-rich motifs, typical for Δ9 acyl-acyl carrier protein (ACP) desaturases. To determine the function of MiΔ9FAD, the gene was heterologously expressed in a Saccharomyces cerevisiae mutant strain with impaired desaturase activity. Results of GC-MS analysis indicated that MiΔ9FAD was able to restore the synthesis of monounsaturated fatty acids, generating palmitoleic acid and oleic acid through the addition of a double bond in the Δ9 position of palmitic acid and stearic acid, respectively.


Assuntos
Ácido Araquidônico/metabolismo , Ácidos Graxos Dessaturases/metabolismo , Microalgas/enzimologia , Saccharomyces cerevisiae/metabolismo , Sequência de Aminoácidos , Clonagem Molecular , Ácidos Graxos Dessaturases/genética , Cromatografia Gasosa-Espectrometria de Massas , Microalgas/genética , Microalgas/crescimento & desenvolvimento , Filogenia , Saccharomyces cerevisiae/genética , Homologia de Sequência de Aminoácidos , Estearoil-CoA Dessaturase
16.
Nan Fang Yi Ke Da Xue Xue Bao ; 36(6): 814-8, 2016 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-27320884

RESUMO

OBJECTIVE: To investigate the effect of diallyl disulfide (DADS) on invasion and metastasis of human breast cancer MCF-7 cells and explore the possible mechanism. METHODS: MCF-7 cells treated with 100, 200, and 400 µmol/L of DADS for 24 h were examined for cell invasion and migration capacities using Transwell assay and wound healing assay, respectively. The protein expression of E-cadherin, vimentin, MMP-9 and p-p38 in the cells were detected with Western blotting. The effect of transforming growth factor-ß1 (TGF-ß1) as the agonist of p38 activity was tested in antagonizing the effects of DADS. RESULTS: DADS inhibited the invasion and migration of MCF-7 cells in a dose-dependent manner, down-regulated the protein expression of Vimentin and MMP-9 and up-regulated E-cadherin expression in the cells. Treatment with TGF-ß1 to up-regulate p38 activity obviously antagonized the inhibitory effect of DADS on the invasion and metastasis of MCF-7 cells. CONCLUSION: DADS can inhibit the invasion and metastasis of MCF-7 cells in vitro by down-regulating p38 activity.


Assuntos
Compostos Alílicos/farmacologia , Neoplasias da Mama/patologia , Dissulfetos/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteína Quinase 11 Ativada por Mitógeno/metabolismo , Antígenos CD , Caderinas/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Células MCF-7/efeitos dos fármacos , Metaloproteinase 9 da Matriz/metabolismo , Invasividade Neoplásica , Metástase Neoplásica , Fator de Crescimento Transformador beta1/farmacologia , Vimentina/metabolismo
17.
Sci Rep ; 6: 26610, 2016 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-27216435

RESUMO

In addition to the Kennedy pathway for de novo biosynthesis, triacylglycerol (TAG), the most important stock for microalgae-based biodiesel production, can be synthesized by phospholipid: diacylglycerol acyltransferase (PDAT) that transfers an acyl group from phospholipids (PLs) to diacylglycerol (DAG). This study presents a novel gene that encodes PDAT from the green microalga Myrmecia incisa Reisigl H4301 (designated MiPDAT ). MiPDAT is localized on the plasma membrane (PM) via the agroinfiltration of tobacco leaves with a green fluorescent protein-fused construct. MiPDAT synthesizes TAG based on functional complementary experiments in the mutant yeast strain H1246 and the membrane lipid phosphatidylcholine (PC) is preferentially used as substrates as revealed by in vitro enzyme activity assay. The gradually increased transcription levels of MiPDAT in M. incisa during the cultivation under nitrogen starvation conditions is proposed to be responsible for the decrease and increase of the PC and TAG levels, respectively, as detected by liquid chromatography-mass spectrometry after 4 d of nitrogen starvation. In addition, the mechanism by which MiPDAT in this microalga uses PC to yield TAG is discussed. Accordingly, it is concluded that this PM-located PDAT contributes to the conversion of membrane lipids into TAG in M. incisa during the nitrogen starvation stress.


Assuntos
Aciltransferases/metabolismo , Clorófitas/metabolismo , Lipídeos de Membrana/metabolismo , Microalgas/metabolismo , Nitrogênio , Proteínas de Plantas/metabolismo , Estresse Fisiológico , Triglicerídeos/biossíntese
18.
Nan Fang Yi Ke Da Xue Xue Bao ; 36(3): 321-6, 2016 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-27063156

RESUMO

OBJECTIVE: To investigate the effects of miR-181b on the migration and invasion of osteosarcoma cells. METHODS: Three cultured osteosarcoma cell lines and MG-63 cells transfected with miR-181b inhibitor were examined for miR-181b expression using qRT-PCR analysis. The cell migration and invasion of the transfected cells were assessed with Transwell assay. The targets of miR-181b were predicted using a miRNA target prediction software and the results were verified with luciferase reporter assay. The target protein expression in osteosarcoma cells lines was determined by Western blotting, and the cell migration and invasion changes following inhibition of miR-181b or its target protein were assessed using Transwell assay. RESULTS: All the 3 osteosarcoma cells lines showed significantly up-regulated miR-181b expression. Inhibition of miR-181b expression obviously suppressed the migration and invasion of MG-63 cells. Based on luciferase reporter assay, N-myc downstream regulated gene 2 (NDRG2) was identified as the direct target gene of miR-181b, and inhibition of NDRG2 expression significantly reversed the effect of miR-181b on cell migration and invasion in MG-63 cells. CONCLUSION: miR-181b is over-expressed in osteosarcoma cells, and inhibition of miR-181b, which directly targets NDRG2, can suppress the migration and invasion of osteosarcoma cells.


Assuntos
Neoplasias Ósseas/patologia , Regulação Neoplásica da Expressão Gênica , MicroRNAs/metabolismo , Osteossarcoma/patologia , Proteínas Supressoras de Tumor/metabolismo , Neoplasias Ósseas/genética , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Humanos , MicroRNAs/genética , Invasividade Neoplásica , Osteossarcoma/genética , Proteínas Supressoras de Tumor/genética
19.
Front Plant Sci ; 7: 286, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27014309

RESUMO

To analyze the contribution of glycerol-3-phosphate acyltransferase (GPAT) to the first acylation of glycerol-3-phosphate (G-3-P), the present study focused on a functional analysis of the GPAT gene from Lobosphaera incisa (designated as LiGPAT). A full-length cDNA of LiGPAT consisting of a 1,305-bp ORF, a 1,652-bp 5'-UTR, and a 354-bp 3'-UTR, was cloned. The ORF encoded a 434-amino acid peptide, of which 63 residues at the N-terminus defined a chloroplast transit peptide. Multiple sequence alignment and phylogeny analysis of GPAT homologs provided the convincible bioinformatics evidence that LiGPAT was localized to chloroplasts. Considering the conservation of His among the G-3-P binding sites from chloroplastidial GPATs and the substitution of His by Arg at position 195 in the LiGPAT mature protein (designated mLiGPAT), we established the heterologous expression of either mLiGPAT or its mutant (Arg195His) (sdmLiGPAT) in the GPAT-deficient yeast mutant gat1Δ. Lipid profile analyses of these transgenic yeasts not only validated the acylation function of LiGPAT but also indicated that the site-directed mutagenesis from Arg(195) to His led to an increase in the phospholipid level in yeast. Semi-quantitative analysis of mLiGPAT and sdmLiGPAT, together with the structural superimposition of their G-3-P binding sites, indicated that the increased enzymatic activity was caused by the enlarged accessible surface of the phosphate group binding pocket when Arg(195) was mutated to His. Thus, the potential of genetic manipulation of GPAT to increase the glycerolipid level in L. incisa and other microalgae would be of great interest.

20.
Oncotarget ; 7(9): 10498-512, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26871290

RESUMO

Diallyl disulfide (DADS) has been shown to have multi-targeted antitumor activities. We have previously discovered that it has a repressive effect on LIM kinase-1 (LIMK1) expression in gastric cancer MGC803 cells. This suggests that DADS may inhibit epithelial-mesenchymal transition (EMT) by downregulating LIMK1, resulting in the inhibition of invasion and growth in gastric cancer. In this study, we reveal that LIMK1 expression is correlated with tumor differentiation, invasion depth, clinical stage, lymph node metastasis, and poor prognosis. DADS downregulated the Rac1-Pak1/Rock1-LIMK1 pathway in MGC803 cells, as shown by decreased p-LIMK1 and p-cofilin1 levels, and suppressed cell migration and invasion. Knockdown and overexpression experiments performed in vitro demonstrated that downregulating LIMK1 with DADS resulted in restrained EMT that was coupled with decreased matrix metalloproteinase-9 (MMP-9) and increased tissue inhibitor of metalloproteinase-3 (TIMP-3) expression. In in vitro and in vivo experiments, the DADS-induced suppression of cell proliferation was enhanced and antagonized by the knockdown and overexpression of LIMK1, respectively. Similar results were observed for DADS-induced changes in the expression of vimentin, CD34, Ki-67, and E-cadherin in xenografted tumors. These results indicate that downregulation of LIMK1 by DADS could explain the inhibition of EMT, invasion and proliferation in gastric cancer cells.


Assuntos
Compostos Alílicos/farmacologia , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Dissulfetos/farmacologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Quinases Lim/metabolismo , Neoplasias Gástricas/patologia , Animais , Antígenos CD34/metabolismo , Caderinas/metabolismo , Linhagem Celular Tumoral , Cofilina 1/metabolismo , Regulação para Baixo , Humanos , Antígeno Ki-67/metabolismo , Quinases Lim/biossíntese , Quinases Lim/genética , Metástase Linfática , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Invasividade Neoplásica/patologia , Transplante de Neoplasias , Neoplasias Gástricas/mortalidade , Inibidor Tecidual de Metaloproteinase-3/metabolismo , Transplante Heterólogo , Vimentina/metabolismo , Quinases Ativadas por p21/biossíntese , Proteínas rac1 de Ligação ao GTP/biossíntese , Quinases Associadas a rho/biossíntese
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA