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1.
PLoS One ; 19(3): e0299902, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38512917

RESUMO

Accurate identification of small tea buds is a key technology for tea harvesting robots, which directly affects tea quality and yield. However, due to the complexity of the tea plantation environment and the diversity of tea buds, accurate identification remains an enormous challenge. Current methods based on traditional image processing and machine learning fail to effectively extract subtle features and morphology of small tea buds, resulting in low accuracy and robustness. To achieve accurate identification, this paper proposes a small object detection algorithm called STF-YOLO (Small Target Detection with Swin Transformer and Focused YOLO), which integrates the Swin Transformer module and the YOLOv8 network to improve the detection ability of small objects. The Swin Transformer module extracts visual features based on a self-attention mechanism, which captures global and local context information of small objects to enhance feature representation. The YOLOv8 network is an object detector based on deep convolutional neural networks, offering high speed and precision. Based on the YOLOv8 network, modules including Focus and Depthwise Convolution are introduced to reduce computation and parameters, increase receptive field and feature channels, and improve feature fusion and transmission. Additionally, the Wise Intersection over Union loss is utilized to optimize the network. Experiments conducted on a self-created dataset of tea buds demonstrate that the STF-YOLO model achieves outstanding results, with an accuracy of 91.5% and a mean Average Precision of 89.4%. These results are significantly better than other detectors. Results show that, compared to mainstream algorithms (YOLOv8, YOLOv7, YOLOv5, and YOLOx), the model improves accuracy and F1 score by 5-20.22 percentage points and 0.03-0.13, respectively, proving its effectiveness in enhancing small object detection performance. This research provides technical means for the accurate identification of small tea buds in complex environments and offers insights into small object detection. Future research can further optimize model structures and parameters for more scenarios and tasks, as well as explore data augmentation and model fusion methods to improve generalization ability and robustness.


Assuntos
Algoritmos , Redes Neurais de Computação , Fontes de Energia Elétrica , Generalização Psicológica , Chá
2.
Org Lett ; 25(38): 7046-7050, 2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37721372

RESUMO

A base-mediated cascade reaction of CF3-imidoyl sulfoxonium ylides and azo compounds has been achieved, allowing for facile access to trifluoromethyl-substituted 1,2-dihydroquinoxalines and diimines in moderate to excellent yields. Noteworthy is that the unusual N-N bond cleavage and rearrangement of azo compounds are involved in the transformations.

3.
Chem Sci ; 13(12): 3526-3532, 2022 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-35432869

RESUMO

The synthesis of diverse products from the same starting materials is always attractive in organic chemistry. Here, a palladium-catalyzed substrate-controlled regioselective functionalization of unactivated alkenes with trifluoroacetimidoyl chlorides has been developed, which provides a direct but controllable access to a variety of structurally diverse trifluoromethyl-containing indoles and indolines. In more detail, with respect to γ,δ-alkenes, 1,1-geminal difunctionalization of unactivated alkenes with trifluoroacetimidoyl chloride enables the [4 + 1] annulation to produce indoles; as for ß,γ-alkenes, a [3 + 2] heteroannulation with the hydrolysis product of trifluoroacetimidoyl chloride through 1,2-vicinal difunctionalization of alkenes occurs to deliver indoline products. The structure of alkene substrates differentiates the regioselectivity of the reaction.

4.
Cardiovasc Res ; 112(2): 581-589, 2016 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-27389411

RESUMO

AIMS: Kv7.4, a voltage-dependent potassium channel expressed throughout the vasculature, controls arterial contraction and is compromised in hypertension by an unknown mechanism. MicroRNAs (miRs) are post-transcriptional regulators of protein production and are altered in disease states such as hypertension. We investigated whether miRs regulate Kv7.4 expression. METHODS AND RESULTS: In renal and mesenteric arteries (MAs) of the spontaneously hypertensive rat (SHR), Kv7.4 protein decreased compared with the normotensive (NT) rat without a decrease in KCNQ4 mRNA, inferring that Kv7.4 abundance was determined by post-transcriptional regulation. In silico analysis of the 3' UTR of KCNQ4 revealed seed sequences for miR26a, miR133a, miR200b, miR153, miR214, miR218, and let-7d with quantitative polymerase chain reaction showing miR153 increased in those arteries from SHRs that exhibited decreased Kv7.4 levels. Luciferase reporter assays indicated a direct targeting effect of miR153 on the 3' UTR of KCNQ4. Introduction of high levels of miR153 to MAs increased vascular wall thickening and reduced Kv7.4 expression/Kv7 channel function compared with vessels receiving a non-targeting miR, providing a proof of concept of Kv7.4 regulation by miR153. CONCLUSION: This study is the first to define a role for aberrant miR153 contributing to the hypertensive state through targeting of KCNQ4 in an animal model of hypertension, raising the possibility of the use of miR153-related therapies in vascular disease.

5.
J Pediatr Gastroenterol Nutr ; 63(6): e169-e175, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27050058

RESUMO

OBJECTIVES: Coagulopathy and mesenteric thrombosis are common in premature neonates with necrotizing enterocolitis (NEC). This pilot study aimed to investigate the hypothesis that there are changes in the gene expression related to the coagulation and anticoagulation systems in NEC. METHODS: Consecutive neonates (n = 11) with NEC (Bell stages 2-3) were recruited. Two comparison groups, matched for birth weight and corrected gestational age, were selected based on the absence of inflammation and coagulopathy (healthy control, n = 10), or the presence of a confirmed blood infection (sepsis control, n = 12). A pathway-specific quantitative polymerase chain reaction array was used to determine the expression of 94 genes involved in human blood coagulation and anticoagulation cascade. RESULTS: Twelve genes of the coagulation and anticoagulation systems were significantly altered in the patients with NEC compared with healthy controls. In particular, neutrophil elastase, CD63, PROS1, HGF, and F12 were significantly upregulated (mean fold changes [FCs] +2.74, P < 0.05) with an overall procoagulant effect; MFGE8, factor II (thrombin) receptor-like 1 (F2RL1), FGL2, PLAT, PROCR, SERPIND1, and HNF4A were significantly downregulated (mean FCs -2.45, P < 0.05) with a reduction in fibrinolysis and endothelial regeneration. In the comparison between NEC and sepsis, we did observe a significant difference in expression of F2RL1 (FC -2.50, P = 0.01). CONCLUSIONS: We have identified potential biomarkers associated with coagulopathy and disease progression in NEC. In particular, the overall procoagulant status, at the transcriptional level, should be further investigated to unveil molecular mechanisms leading to intestinal necrosis, multiorgan failure, and death.


Assuntos
Coagulação Sanguínea/genética , Enterocolite Necrosante/genética , Expressão Gênica , Biomarcadores/sangue , Testes de Coagulação Sanguínea , Estudos de Casos e Controles , Progressão da Doença , Enterocolite Necrosante/sangue , Enterocolite Necrosante/complicações , Feminino , Idade Gestacional , Humanos , Lactente , Recém-Nascido de Peso Extremamente Baixo ao Nascer , Lactente Extremamente Prematuro , Recém-Nascido , Masculino , Projetos Piloto , Estudos Prospectivos , Reação em Cadeia da Polimerase em Tempo Real , Sepse/complicações , Sepse/genética
6.
Metallomics ; 6(1): 154-65, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24301558

RESUMO

Much remains to be understood about systemic regulation of zinc uptake in vertebrates, and adequate zinc status is far from always achieved in animals or human. In addition to absorbing zinc from the diet, fish are able to take up zinc directly from the water with the gills. This provides an elegant system to study zinc uptake, how it relates to zinc status, and the expression of genes for proteins involved in zinc acquisition. A 21-day experiment was conducted in which zebrafish were acclimated to deficient, control or excess zinc concentrations in the water and feed. Deficient provision of zinc reduced whole body zinc, potassium, sodium and calcium levels whilst zinc concentrations in the uptake epithelia (gills and gut) remained unchanged. Excess levels of zinc caused accumulation of zinc in the gills, intestine and carcass, but impaired whole body iron, sodium and calcium concentrations. Fish subjected to zinc deficiency had, surprisingly, a reduced zinc influx across the gill epithelium, even when tested at a high concentration of zinc in the water. Zinc influx in the excess group was indistinct from the control. Expression of genes for metallothionein-2 (Mt2) and zinc transporters-1, -2, and -8 (Znt1, Znt2, Znt8) in uptake epithelia showed in general a direct relationship with zinc supply, while mRNA for Zip4 was inversely related to zinc supply. Transcripts for the epithelial calcium channel (Ecac/Trpv6) showed time-dependent increased expression in the gills of the deficiency group, and a transient decrease of expression during zinc excess. Transcriptome profiling by microarrays showed that in both gills and intestine, the most markedly affected biological functions were those related to cell growth, proliferation and cancer, closely followed by processes of gene transcription and protein synthesis in general. Whilst changes in zinc supply had profound effects in the intestine on genes associated with uptake and metabolism of macronutrients, many of the unique categories of genes preferentially regulated in the gill could be mapped onto signalling pathways. This included pathways for PPAR/RXR, LXR/RXR, ATM, chemokine, and BMP signalling. Overall, the responses of epithelial tissue to zinc deficiency and excess are best explained by local epithelial homeostasis with no evidence of systemic control.


Assuntos
Brânquias/metabolismo , Homeostase/fisiologia , Mucosa Intestinal/metabolismo , Zinco/metabolismo , Análise de Variância , Animais , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Análise por Conglomerados , Homeostase/efeitos dos fármacos , Homeostase/genética , Metalotioneína/genética , Metalotioneína/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Análise de Componente Principal , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo , Transcriptoma/efeitos dos fármacos , Transcriptoma/genética , Peixe-Zebra/genética , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo , Zinco/farmacocinética , Zinco/farmacologia
7.
FEBS Lett ; 586(23): 4165-72, 2012 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-23092882

RESUMO

The MAPK/ERK signalling pathway has been described to mediate IL-1 induction of target genes and is known to be regulated by microRNAs (miRNA). We describe a novel miRNA regulating the expression of the MEK1 gene and how it impacts IL-1 induced IL-6 transcription. miR-497 was predicted to target MEK1 3'UTR using bioinformatic tools. Transfection of miR-497 into HeLa cells inhibited MEK1 protein expression by 50%. In transient transfection experiments, the luciferase activity of a MEK1 3'UTR luciferase reporter construct was reduced in the presence of miR-497, and mutation of the predicted miR-497 binding site restored activity. miR-497 also decreased protein levels of RAF1 and ERK1 but not ERK2. Addition of miR-497 was further shown to inhibit IL-1 induced IL-6 gene transcription.


Assuntos
Regiões 3' não Traduzidas/genética , Interleucina-1/farmacologia , Interleucina-1beta/farmacologia , Interleucina-6/genética , MicroRNAs/genética , Células HeLa , Humanos , MAP Quinase Quinase 1/genética , MicroRNAs/fisiologia
8.
Cytokine ; 60(1): 108-13, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22673037

RESUMO

UNLABELLED: Previous epidemiologic studies have evaluated the use of immunological markers as possible tools for measuring ageing and predicting age-related pathology. The importance of both genetic and environmental influences in regulation of these markers has been emphasized. In order to further evaluate this relationship, the present study aims to investigate the relative influence of genetic and environmental factors on four key cytokines involved in the human immune response (Interleukin (IL)-1ß, IL-6, IL-10 and Tumor Necrosis Factor (TNF)-α). In addition, the role of age as a possible moderator on these influences was evaluated. METHODS: The study was conducted in 1603 females from the Twins UK registry, with mean age ± SD of 60.4 ± 12.2 years, including 863 monozygotic twins (385 pairs and 93 singletons) and 740 dizygotic twins (321 pairs and 98 singletons). Heritability was estimated using structural equation modeling. The role of age as a moderator was evaluated using gene-age interaction models. RESULTS: Heritabilities were moderate for IL-1ß (range: 0.27-0.32) and IL-10 (0.30) and low for IL-6 (range: 0.15-0.16) and TNF-α (range: 0.17-0.23). For IL-1ß, heritability declines with age due to an increase in unique environmental factors. For TNF-α, heritability increases with age due to a decrease in unique environmental factors. CONCLUSION: The current findings illustrate the importance of genetic and environmental influences on four cytokines involved in the human immune response. For two of these there is evidence that heritability changes with age owing to changes in environmental factors unique to the individual.


Assuntos
Envelhecimento , Interleucina-10/sangue , Interleucina-1beta/sangue , Interleucina-6/sangue , Fator de Necrose Tumoral alfa/sangue , Idoso , Análise de Variância , Feminino , Humanos , Pessoa de Meia-Idade , Modelos Genéticos , Gêmeos Dizigóticos/genética , Gêmeos Monozigóticos/genética
9.
J Am Coll Cardiol ; 60(9): 841-50, 2012 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-22682551

RESUMO

OBJECTIVES: This study sought to determine whether variations in NOS1AP affect drug-induced long QT syndrome (LQTS). BACKGROUND: Use of antiarrhythmic drugs is limited by the high incidence of serious adverse events including QT prolongation and torsades de pointes. NOS1AP gene variants play a role in modulating QT intervals in healthy subjects and severity of presentation in LQTS. METHODS: This study carried out an association study using 167 single nucleotide polymorphisms (SNP) spanning the NOS1AP gene in 58 Caucasian patients experiencing drug-induced LQTS (dLQTS) and 87 Caucasian controls from the DARE (Drug-Induced Arrhythmia Risk Evaluation) study. RESULTS: The rs10800397 SNP was significantly associated with dLQTS (odds ratio [OR]: 3.3, 99.95% confidence interval [CI]: 1.0 to 10.8, p = 3.7 × 10(-4)). The associations were more pronounced in the subgroup of amiodarone users, in which 3 SNPs, including rs10800397, were significantly associated (most significant SNP: rs10919035: OR: 5.5, 99.95% CI: 1.1 to 27.9, p = 3.0 × 10(-4)). We genotyped rs10919035 in an independent replication cohort of 28 amiodarone dLQTS cases versus 173 control subjects (meta-analysis of both studies: OR: 2.81, 99.95% CI: 1.62 to 4.89, p = 2.4 × 10(-4)). Analysis of corrected QT interval among 74 control subjects from our dataset showed a similar pattern of significance over the gene region as the case-control analysis. This pattern was confirmed in 1,480 control subjects from the BRIGHT (British Genetics of Hypertension Study) cohort (top SNP from DARE: rs12734991 in meta-analysis: increase in corrected QT interval per C allele: 9.1 ± 3.2 ms, p = 1.7 × 10(-4)). CONCLUSIONS: These results provide the first demonstration that common variations in the NOS1AP gene are associated with a significant increase in the risk of dLQTS. This study suggests that common variations in the NOS1AP gene may have relevance for future pharmacogenomic applications in clinical practice permitting safer prescription of drugs for vulnerable patients.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Amiodarona/efeitos adversos , Antiarrítmicos/efeitos adversos , Síndrome do QT Longo/induzido quimicamente , Torsades de Pointes/induzido quimicamente , Fibrilação Ventricular/induzido quimicamente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Humanos , Síndrome do QT Longo/genética , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , Torsades de Pointes/genética , Fibrilação Ventricular/genética , Adulto Jovem
10.
BMC Genomics ; 11: 553, 2010 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-20937081

RESUMO

BACKGROUND: Dietary zinc supplementation may help to promote growth, boost the immune system, protect against diabetes, and aid recovery from diarrhoea. We exploited the zebrafish (Danio rerio) gill as a unique vertebrate ion transporting epithelium model to study the time-dependent regulatory networks of gene-expression leading to homeostatic control during zinc supplementation. This organ forms a conduit for zinc uptake whilst exhibiting conservation of zinc trafficking components. RESULTS: Fish were maintained with either zinc supplemented water (4.0 µM) and diet (2023 mg zinc kg-1) or water and diet containing Zn2+ at 0.25 µM and 233 mg zinc kg-1, respectively. Gill tissues were harvested at five time points (8 hours to 14 days) and transcriptome changes analysed in quintuplicate using a 16 K microarray with results anchored to gill Zn2+ influx and whole body nutrient composition (protein, carbohydrate, lipid, elements). The number of regulated genes increased up to day 7 but declined as the fish acclimated. In total 525 genes were regulated (having a fold-change more than 1.8 fold change and an adjusted P-value less than 0.1 which is controlling a 10% False discovery rate, FDR) by zinc supplementation, but little overlap was observed between genes regulated at successive time-points. Many genes displayed cyclic expression, typical for homeostatic control mechanisms. Annotation enrichment analysis revealed strong overrepresentation of "transcription factors", with specific association evident with "steroid hormone receptors". A suite of genes linked to "development" were also statistically overrepresented. More specifically, early regulation of genes was linked to a few key transcription factors (e.g. Mtf1, Jun, Stat1, Ppara, Gata3) and was followed by hedgehog and bone morphogenic protein signalling. CONCLUSIONS: The results suggest that zinc supplementation reactivated developmental pathways in the gill and stimulated stem cell differentiation, a response likely reflecting gill remodelling in response to its altered environment. This provides insight to the role of zinc during cell differentiation and illustrates the critical nature of maintaining zinc status. The study also highlights the importance of temporal transcriptomics analysis in order resolve the discrete elements of biological processes, such as zinc acclimation.


Assuntos
Suplementos Nutricionais , Perfilação da Expressão Gênica , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Peixe-Zebra/genética , Zinco/farmacologia , Regiões 5' não Traduzidas/genética , Animais , Sítios de Ligação , Regulação da Expressão Gênica/efeitos dos fármacos , Redes Reguladoras de Genes/genética , Anotação de Sequência Molecular , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Fatores de Tempo , Fatores de Transcrição/metabolismo , Transcrição Gênica/efeitos dos fármacos , Peixe-Zebra/fisiologia , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
11.
BMC Genomics ; 11: 548, 2010 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-20932299

RESUMO

BACKGROUND: Zinc deficiency is detrimental to organisms, highlighting its role as an essential micronutrient contributing to numerous biological processes. To investigate the underlying molecular events invoked by zinc depletion we performed a temporal analysis of transcriptome changes observed within the zebrafish gill. This tissue represents a model system for studying ion absorption across polarised epithelial cells as it provides a major pathway for fish to acquire zinc directly from water whilst sharing a conserved zinc transporting system with mammals. RESULTS: Zebrafish were treated with either zinc-depleted (water = 2.61 µg L-1; diet = 26 mg kg-1) or zinc-adequate (water = 16.3 µg L-1; diet = 233 mg kg-1) conditions for two weeks. Gill samples were collected at five time points and transcriptome changes analysed in quintuplicate using a 16K oligonucleotide array. Of the genes represented the expression of a total of 333 transcripts showed differential regulation by zinc depletion (having a fold-change greater than 1.8 and an adjusted P-value less than 0.1, controlling for a 10% False Discovery Rate). Down-regulation was dominant at most time points and distinct sets of genes were regulated at different stages. Annotation enrichment analysis revealed that 'Developmental Process' was the most significantly overrepresented Biological Process GO term (P = 0.0006), involving 26% of all regulated genes. There was also significant bias for annotations relating to development, cell cycle, cell differentiation, gene regulation, butanoate metabolism, lysine degradation, protein tyrosin phosphatases, nucleobase, nucleoside and nucleotide metabolism, and cellular metabolic processes. Within these groupings genes associated with diabetes, bone/cartilage development, and ionocyte proliferation were especially notable. Network analysis of the temporal expression profile indicated that transcription factors foxl1, wt1, nr5a1, nr6a1, and especially, hnf4a may be key coordinators of the homeostatic response to zinc depletion. CONCLUSIONS: The study revealed the complex regulatory pathways that allow the organism to subtly respond to the low-zinc condition. Many of the processes affected reflected a fundamental restructuring of the gill epithelium through reactivation of developmental programs leading to stem cell differentiation. The specific regulation of genes known to be involved in development of diabetes provides new molecular links between zinc deficiency and this disease. The present study demonstrates the importance of including the time-dimension in microarray studies.


Assuntos
Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Brânquias/metabolismo , Peixe-Zebra/genética , Zinco/deficiência , Regiões 5' não Traduzidas/genética , Animais , Sítios de Ligação , Regulação da Expressão Gênica/efeitos dos fármacos , Redes Reguladoras de Genes/efeitos dos fármacos , Genes Reguladores/genética , Brânquias/efeitos dos fármacos , Anotação de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Ligação Proteica/efeitos dos fármacos , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Fatores de Tempo , Fatores de Transcrição/metabolismo , Peixe-Zebra/fisiologia , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo , Zinco/farmacologia
12.
PLoS One ; 4(7): e6138, 2009 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-19587794

RESUMO

To identify loci affecting the electrocardiographic QT interval, a measure of cardiac repolarisation associated with risk of ventricular arrhythmias and sudden cardiac death, we conducted a meta-analysis of three genome-wide association studies (GWAS) including 3,558 subjects from the TwinsUK and BRIGHT cohorts in the UK and the DCCT/EDIC cohort from North America. Five loci were significantly associated with QT interval at P<1x10(-6). To validate these findings we performed an in silico comparison with data from two QT consortia: QTSCD (n = 15,842) and QTGEN (n = 13,685). Analysis confirmed the association between common variants near NOS1AP (P = 1.4x10(-83)) and the phospholamban (PLN) gene (P = 1.9x10(-29)). The most associated SNP near NOS1AP (rs12143842) explains 0.82% variance; the SNP near PLN (rs11153730) explains 0.74% variance of QT interval duration. We found no evidence for interaction between these two SNPs (P = 0.99). PLN is a key regulator of cardiac diastolic function and is involved in regulating intracellular calcium cycling, it has only recently been identified as a susceptibility locus for QT interval. These data offer further mechanistic insights into genetic influence on the QT interval which may predispose to life threatening arrhythmias and sudden cardiac death.


Assuntos
Proteínas de Ligação ao Cálcio/genética , Variação Genética , Estudo de Associação Genômica Ampla , Coração/fisiologia , Cromossomos Humanos Par 6 , Estudos de Coortes , Humanos
13.
Toxicol Sci ; 110(2): 389-400, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19465457

RESUMO

The greatest source of human exposure to methylmercury (MeHg) is the diet, in particular the consumption of seafood. To investigate the importance of dietary MeHg speciation on neurotoxicity, balb/c mice dams were exposed to MeHgCys (the naturally-occurring salt) and MeHgCl (the laboratory salt), at concentrations up to 4.5 mg/kg, for 11 weeks (inclusive of 3 weeks gestational and 2 weeks post-partum exposure). Impacts of developmental exposure were assessed in their offspring by monitoring transcriptomic (brain gene expression via microarray and quantitative PCR), tissue mercury (Hg) accumulation, and neurobehavioral endpoints. There were no differences in tissue Hg accumulation between the two forms of MeHg presented, but differences in pup behavior and gene expression endpoints were noted. For example, MeHgCl, but not MeHgCys, impaired pup activity in an open field assessment. Similar impacts of MeHgCl were noted in adults. A total of 131 genes were differentially-regulated in pup brains following maternal exposure to MeHg, 50 of which were specific to MeHgCys and 35 specific to MeHgCl. Regulated genes were significantly enriched for several annotation categories including metal/zinc-binding and transcription regulation. In contrast few antioxidant genes were differentially regulated. This analysis provided insight into mechanisms by which MeHg may impair cellular processes in addition to behavioral impairments such as those associated with learning and memory. The results show differences between the toxic impacts of MeHg species, and also highlight the potential utility of an integrated approach incorporating gene expression with behavioral endpoints.


Assuntos
Comportamento Animal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Cisteína/análogos & derivados , Intoxicação do Sistema Nervoso por Mercúrio/etiologia , Compostos de Metilmercúrio/toxicidade , Efeitos Tardios da Exposição Pré-Natal , Poluentes Químicos da Água/toxicidade , Envelhecimento , Fenômenos Fisiológicos da Nutrição Animal , Animais , Animais Recém-Nascidos , Carga Corporal (Radioterapia) , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Cisteína/metabolismo , Cisteína/toxicidade , Dieta , Feminino , Contaminação de Alimentos , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica/efeitos dos fármacos , Idade Gestacional , Fenômenos Fisiológicos da Nutrição Materna , Intoxicação do Sistema Nervoso por Mercúrio/genética , Intoxicação do Sistema Nervoso por Mercúrio/fisiopatologia , Compostos de Metilmercúrio/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Análise de Sequência com Séries de Oligonucleotídeos , Gravidez , RNA Mensageiro/metabolismo , Reflexo/efeitos dos fármacos , Reprodução/efeitos dos fármacos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Poluentes Químicos da Água/metabolismo
14.
Biochem Soc Trans ; 36(Pt 6): 1252-7, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19021535

RESUMO

There is a growing appreciation for the diverse roles of zinc as a signalling substance in biological systems. Zinc signalling is brought about by changes in intracellular concentrations of labile Zn(2+), resulting in both genomic and non-genomic effects. The genomic responses are largely mediated by MTF1 (metal-regulatory transcription factor 1), which binds to MREs (metal-response elements) in the 5' regulatory region of genes in response to zinc. Treatment of cultured zebrafish ZF4 cells with siRNA (small interfering RNA) to MTF1 changed the transcriptional response to zinc for over 1000 genes, as assessed using an oligonucleotide microarray. From this primary list of MTF1-dependent genes, we identified a relatively small cohort that showed a configuration of MREs in their 5' regulatory regions similar to known MTF1 targets. This group showed a remarkable dominance of nucleic acid-binding proteins and other proteins involved in embryological development, implicating MTF1 as a master regulator of gene expression during development.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Fatores de Transcrição/metabolismo , Peixe-Zebra/genética , Zinco/farmacologia , Animais , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Ligação a DNA/genética , Redes Reguladoras de Genes/efeitos dos fármacos , Metalotioneína/genética , Metalotioneína/metabolismo , Modelos Animais , RNA Interferente Pequeno/metabolismo , Fatores de Transcrição/genética , Fator MTF-1 de Transcrição
15.
Physiol Genomics ; 34(2): 205-14, 2008 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-18477665

RESUMO

Resolving the mechanisms underlying the temporal and spatial profile of zinc transporter expression in response to zinc availability is key to understanding zinc homeostasis. The mRNA expression of seven zinc transporters was studied in zebrafish gills when treated with zinc deficiency/excess over a 14-day period. Of these, ZnT1, ZnT5, ZIP3, and ZIP10 were differentially expressed in response to changed zinc status. The mRNA level of zinc exporter, ZnT1, was upregulated in fish subjected to excess zinc and downregulated by zinc deprivation. This response was similar to that of metallothionein-2 (MT2). Zinc deficiency caused an increased abundance of mRNA for zinc importers ZnT5, ZIP3, and ZIP10. Expression of ZnT5 and ZIP10, but not ZIP3, was inhibited by excess zinc. Zinc influx function of ZIP10 was demonstrated by (65)Zn transport assays in Xenopus oocyte expression experiments, suggesting that the inverse relationship between zinc availability and ZIP10 expression serves to maintain zinc homeostasis. Two distinct transcription start sites (TSS) for ZIP10 were found in gill and kidney. Luciferase assays and mutation/deletion analysis of DNA fragments proximal to the respective TSS revealed that ZIP10 has two alternative promoters (P1 and P2) displaying opposite regulatory control in response to zinc status. Positive as well as negative regulation by zinc involves MRE clusters in the respective promoters. These results provide experimental evidence for MREs functioning as repressor elements, implicating MTF1 involvement in the negative regulation of ZIP10. This is in contrast to the well-established positive regulation by MTF1 of other genes, such as MT2 and ZnT1.


Assuntos
Proteínas de Transporte/genética , Brânquias/metabolismo , Elementos de Resposta/genética , Transcrição Gênica/efeitos dos fármacos , Proteínas de Peixe-Zebra/genética , Peixe-Zebra/genética , Zinco/farmacologia , Regiões 5' não Traduzidas/genética , Animais , Sequência de Bases , Proteínas de Transporte/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Íntrons/genética , Luciferases/metabolismo , Metalotioneína/genética , Metalotioneína/metabolismo , Dados de Sequência Molecular , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Sítio de Iniciação de Transcrição , Proteínas de Peixe-Zebra/metabolismo
16.
Biochim Biophys Acta ; 1732(1-3): 88-95, 2005 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-16500426

RESUMO

In contrast to mammals, zinc transporter genes remain largely uncharacterised in teleosts. Teleost zinc transporter genes were data-mined and phylogenetically assigned to mammalian orthologues. For the first time in animals, the tissue-distribution and mRNA expression response to zinc for most zinc transporter genes was tested in zebrafish.


Assuntos
Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Perfilação da Expressão Gênica , Filogenia , Peixe-Zebra/genética , Zinco/metabolismo , Zinco/farmacologia , Animais , Humanos , Especificidade de Órgãos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Peixe-Zebra/metabolismo
17.
Nucleic Acids Res ; 32(19): 5874-93, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15520470

RESUMO

The Escherichia coli cyclic AMP receptor protein (CRP) is a global regulator that controls transcription initiation from more than 100 promoters by binding to a specific DNA sequence within cognate promoters. Many genes in the CRP regulon have been predicted simply based on the presence of DNA-binding sites within gene promoters. In this study, we have exploited a newly developed technique, run-off transcription/microarray analysis (ROMA) to define CRP-regulated promoters. Using ROMA, we identified 176 operons that were activated by CRP in vitro and 16 operons that were repressed. Using positive control mutants in different regions of CRP, we were able to classify the different promoters into class I or class II/III. A total of 104 operons were predicted to contain Class II CRP-binding sites. Sequence analysis of the operons that were repressed by CRP revealed different mechanisms for CRP inhibition. In contrast, the in vivo transcriptional profiles failed to identify most CRP-dependent regulation because of the complexity of the regulatory network. Analysis of these operons supports the hypothesis that CRP is not only a regulator of genes required for catabolism of sugars other than glucose, but also regulates the expression of a large number of other genes in E.coli. ROMA has revealed 152 hitherto unknown CRP regulons.


Assuntos
Proteína Receptora de AMP Cíclico/metabolismo , Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Regulon , Sequência de Bases , Sítios de Ligação , Proteína Receptora de AMP Cíclico/genética , Escherichia coli/metabolismo , Perfilação da Expressão Gênica , Dados de Sequência Molecular , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Óperon , Regiões Promotoras Genéticas , Transcrição Gênica
18.
Nucleic Acids Res ; 31(16): 4689-95, 2003 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-12907708

RESUMO

We have compiled and aligned the DNA sequences of 554 promoter regions from Escherichia coli and analysed the alignment for sequence similarities. We have focused on the similarities and differences between promoters that either do or do not contain an extended -10 element. The distribution of -10 and -35 hexamer element sequences, the range of spacer lengths between these elements and the frequencies of occurrence of different nucleotides, dinucleotides and trinucleotides were investigated. Extended -10 promoters, which contain a 5'-TG-3' element, tend to have longer spacer lengths than promoters that do not. They also tend to show fewer matches to the consensus -35 hexamer element and contain short runs of T residues in the spacer region. We have shown experimentally that the extended -10 5'-TG-3' motif contributes to promoter activity at seven different promoters. The importance of the motif at different promoters is dependent on the sequence of other promoter elements.


Assuntos
Escherichia coli/genética , Regiões Promotoras Genéticas/genética , 3-Desoxi-7-Fosfo-Heptulonato Sintase/genética , Sequência de Bases , Sequência Conservada/genética , DNA Girase/genética , Regulação Bacteriana da Expressão Gênica , Óperon Lac/genética , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Mutação , Porinas/genética , Sequências Reguladoras de Ácido Nucleico/genética , Alinhamento de Sequência , Homologia de Sequência do Ácido Nucleico , Transcrição Gênica
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