Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 63
Filtrar
1.
Sensors (Basel) ; 24(11)2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38894421

RESUMO

Steel structures are susceptible to corrosion due to their exposure to the environment. Currently used non-destructive techniques require inspector involvement. Inaccessibility of the defective part may lead to unnoticed corrosion, allowing the corrosion to propagate and cause catastrophic structural failure over time. Autonomous corrosion detection is essential for mitigating these problems. This study investigated the effect of the type of encoder-decoder neural network and the training strategy that works the best to automate the segmentation of corroded pixels in visual images. Models using pre-trained DesnseNet121 and EfficientNetB7 backbones yielded 96.78% and 98.5% average pixel-level accuracy, respectively. Deeper EffiecientNetB7 performed the worst, with only 33% true-positive values, which was 58% less than ResNet34 and the original UNet. ResNet 34 successfully classified the corroded pixels, with 2.98% false positives, whereas the original UNet predicted 8.24% of the non-corroded pixels as corroded when tested on a specific set of images exclusive to the investigated training dataset. Deep networks were found to be better for transfer learning than full training, and a smaller dataset could be one of the reasons for performance degradation. Both fully trained conventional UNet and ResNet34 models were tested on some external images of different steel structures with different colors and types of corrosion, with the ResNet 34 backbone outperforming conventional UNet.

2.
World J Microbiol Biotechnol ; 40(8): 251, 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38910228

RESUMO

Genetic diversity in Sclerotium rolfsii is useful for understanding its population structure, identifying different mycelial compatibility groups (MCGs), and developing targeted strategies for disease management in affected crops. In our study, a comprehensive genetic analysis was conducted on 50 isolates of S. rolfsii, collected from various geographic regions and host plants. Two specific genes, TEF1α and RPB2, were utilized to assess the genetic diversity and relationships among these isolates. Notably, out of 1225 pairings examined, only 154 exhibited a compatible reaction, while the majority displayed antagonistic reactions, resulting in the formation of a barrier zone. The isolates were grouped into 10 distinct MCGs. These MCGs were further characterized using genetic sequencing. TEF1α sequences distinguished the isolates into 17 distinct clusters, and RPB2 sequences classified them into 20 clusters. Some MCGs shared identical gene sequences within each gene, while others exhibited unique sequences. Intriguingly, when both TEF1α and RPB2 sequences were combined, all 10 MCGs were effectively differentiated, even those that appeared identical with single-gene analysis. This combined approach provided a comprehensive understanding of the genetic diversity and relationships among the S. rolfsii isolates, allowing for precise discrimination between different MCGs. The results shed light on the population structure and genetic variability within this plant pathogenic fungus, providing valuable insights for disease management and control strategies. This study highlights the significance of comprehending the varied virulence characteristics within S. rolfsii isolates, categorizing them into specific virulence groups based on disease severity index (DSI) values. The association with MCGs provides additional insights into the genetic underpinnings of virulence in this pathogen. Furthermore, the identification of geographical patterns in virulence implies the influence of region-specific factors, with potential implications for disease control and crop protection strategies.Please confirm if the author names are presented accurately and in the correct sequence (given name, middle name/initial, family name). Author 1 Given name: [G. M. Sandeep] Last name [Kumar]. Author 2 Given name: [Praveen Kumar] Last name [Singh]. Also, kindly confirm the details in the metadata are correct.I confirm that the given names are accurate and presented in the correct sequence.


Assuntos
Basidiomycota , Variação Genética , Tipagem de Sequências Multilocus , Filogenia , Doenças das Plantas , Doenças das Plantas/microbiologia , Basidiomycota/genética , Basidiomycota/isolamento & purificação , Basidiomycota/classificação , Micélio/genética , Proteínas Fúngicas/genética , DNA Fúngico/genética , Produtos Agrícolas/microbiologia
3.
Development ; 147(21)2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32541007

RESUMO

Wilms' tumor (WT) morphologically resembles the embryonic kidney, consisting of blastema, epithelial and stromal components, suggesting tumors arise from the dysregulation of normal development. ß-Catenin activation is observed in a significant proportion of WTs; however, much remains to be understood about how it contributes to tumorigenesis. Although activating ß-catenin mutations are observed in both blastema and stromal components of WT, current models assume that activation in the blastemal lineage is causal. Paradoxically, studies performed in mice suggest that activation of ß-catenin in the nephrogenic lineage results in loss of nephron progenitor cell (NPC) renewal, a phenotype opposite to WT. Here, we show that activation of ß-catenin in the stromal lineage non-autonomously prevents the differentiation of NPCs. Comparisons of the transcriptomes of kidneys expressing an activated allele of ß-catenin in the stromal or nephron progenitor cells reveals that human WT more closely resembles the stromal-lineage mutants. These findings suggest that stromal ß-catenin activation results in histological and molecular features of human WT, providing insights into how alterations in the stromal microenvironment may play an active role in tumorigenesis.


Assuntos
Diferenciação Celular , Néfrons/patologia , Células-Tronco/metabolismo , Tumor de Wilms/metabolismo , Tumor de Wilms/patologia , beta Catenina/metabolismo , Animais , Sequência de Bases , Padronização Corporal/genética , Diferenciação Celular/genética , Linhagem da Célula/genética , Epitélio/embriologia , Fatores de Transcrição Forkhead/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Integrases/metabolismo , Mesoderma/embriologia , Camundongos , Mutação/genética , Néfrons/metabolismo , Organogênese/genética , Osteogênese/genética , Células Estromais/metabolismo , Células Estromais/patologia , Transcriptoma/genética , Tumor de Wilms/genética , beta Catenina/genética
4.
Development ; 147(15)2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32586976

RESUMO

Kidney formation requires the coordinated growth of multiple cell types including the collecting ducts, nephrons, vasculature and interstitium. There is a long-held belief that interactions between progenitors of the collecting ducts and nephrons are primarily responsible for kidney development. However, over the last several years, it has become increasingly clear that multiple aspects of kidney development require signaling from the interstitium. How the interstitium orchestrates these various roles is poorly understood. Here, we show that during development the interstitium is a highly heterogeneous patterned population of cells that occupies distinct positions correlated to the adjacent parenchyma. Our analysis indicates that the heterogeneity is not a mere reflection of different stages in a linear developmental trajectory but instead represents several novel differentiated cell states. Further, we find that ß-catenin has a cell autonomous role in the development of a medullary subset of the interstitium and that this non-autonomously affects the development of the adjacent epithelia. These findings suggest the intriguing possibility that the different interstitial subtypes may create microenvironments that play unique roles in development of the adjacent epithelia and endothelia.


Assuntos
Diferenciação Celular , Túbulos Renais Coletores/embriologia , Transdução de Sinais , Animais , Túbulos Renais Coletores/citologia , Camundongos , Camundongos Transgênicos , Células Estromais/citologia , Células Estromais/metabolismo
5.
J Am Soc Nephrol ; 33(9): 1694-1707, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35918150

RESUMO

BACKGROUND: The embryonic renal stroma consists of multiple molecularly distinct cell subpopulations, the functional significance of which is largely unknown. Previous work has demonstrated that the transcription factors YAP and TAZ play roles in the development and morphogenesis of the nephrons, collecting ducts, and nephron progenitor cells. METHODS: In embryonic mouse kidneys, we identified a subpopulation of stromal cells with enriched activity in YAP and TAZ. To evaluate the function of these cell types, we genetically ablated both Yap and Taz from the stromal progenitor population and examined how gene activity and development of YAP/TAZ mutant kidneys are affected over a developmental time course. RESULTS: We found that YAP and TAZ are active in a subset of renal interstitium and that stromal-specific coablation of YAP/TAZ disrupts cortical fibroblast, pericyte, and myofibroblast development, with secondary effects on peritubular capillary differentiation. We also demonstrated that the transcription factor SRF cooperates with YAP/TAZ to drive expression of at least a subset of renal myofibroblast target genes and to specify myofibroblasts but not cortical fibroblasts or pericytes. CONCLUSIONS: These findings reveal a critical role for YAP/TAZ in specific embryonic stromal cells and suggest that interaction with cofactors, such as SRF, influence the expression of cell type-specific target genes, thus driving stromal heterogeneity. Further, this work reveals functional roles for renal stroma heterogeneity in creating unique microenvironments that influence the differentiation and maintenance of the renal parenchyma.


Assuntos
Miofibroblastos , Fatores de Transcrição , Animais , Camundongos , Fatores de Transcrição/metabolismo , Miofibroblastos/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas de Sinalização YAP , Rim/metabolismo
6.
Dev Biol ; 440(1): 13-21, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29705331

RESUMO

Formation of a functional kidney depends on the balance between renewal and differentiation of nephron progenitors. Failure to sustain this balance can lead to kidney failure or stem cell tumors. For nearly 60 years, we have known that signals from an epithelial structure known as the ureteric bud were essential for maintaining this balance. More recently it was discovered that one molecule, Wnt9b, was necessary for both renewal and differentiation of the nephron progenitor cells. How one ligand signaling through one transcription factor promoted two seemingly contradictory cellular processes was unclear. In this study, we show that Wnt9b/beta-catenin signaling alone is sufficient to promote both renewal and differentiation. Moreover, we show that discrete levels of beta-catenin can promote these two disparate fates, with low levels fostering progenitor renewal and high levels driving differentiation. These results provide insight into how Wnt9b regulates distinct target genes that balance nephron progenitor renewal and differentiation.


Assuntos
Néfrons/fisiologia , beta Catenina/metabolismo , beta Catenina/fisiologia , Animais , Diferenciação Celular/genética , Regulação da Expressão Gênica/genética , Rim/citologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Néfrons/embriologia , Transdução de Sinais/fisiologia , Células-Tronco/metabolismo , Células-Tronco/fisiologia , Fatores de Transcrição/metabolismo , Proteínas Wnt/metabolismo , Via de Sinalização Wnt/fisiologia
7.
Arch Virol ; 164(11): 2799-2804, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31440810

RESUMO

Thrips palmi transmits the tospoviruses watermelon bud necrosis (WBNV) and groundnut bud necrosis virus (GBNV) in persistent propagative way. Little is known about the T. palmi-WBNV and -GBNV relationship. In this study, we report the effects of WBNV and GBNV infection on the life history traits of T. palmi. Both WBNV and GBNV had some negative effects on the adult life span, fecundity and survival of T. palmi as compared to non-exposed T. palmi. Tospovirus exposure favoured a female-biased ratio in the experimental population.


Assuntos
Insetos Vetores/virologia , Doenças das Plantas/virologia , Tisanópteros/virologia , Tospovirus/crescimento & desenvolvimento , Animais , Feminino , Masculino , Plantas/virologia , Tospovirus/genética
8.
Anal Chem ; 90(19): 11589-11598, 2018 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-30191710

RESUMO

We have developed innovative assays that can detect enzymes rapidly. Paracetamol- or catechol-bearing compounds, when exposed to their respective enzymes, released paracetamol or catechol, which can be detected using a standard glucose meter. This approach was used to detect a number of diverse analytes that include enzymes such as ß-galactosidase and α-mannosidase and pathogens such as influenza viruses, Streptococcus pneumoniae, and E. coli rapidly. The limit of detection for all analytes was extremely low and clinically relevant for influenza viruses. We also demonstrate that glucose oxidase or glucose dehydrogenase is not required because the paracetamol gets oxidized directly on the electrode surface. This indicates that test strips without glucose oxidase or dehydrogenase can be used, and we can detect analytes in the presence of high levels of background glucose. We demonstrate this unique nature of the assay to detect paracetamol in simulated urine and sheep blood without background interference of intrinsic glucose, indicating that glucose meters can be used to detect nonglucose analytes without background glucose interference.


Assuntos
Proteínas de Bactérias/análise , Análise Química do Sangue/métodos , Escherichia coli/enzimologia , Orthomyxoviridae/enzimologia , Streptococcus pneumoniae/enzimologia , Proteínas Virais/análise , alfa-Galactosidase/análise , alfa-Manosidase/análise , Animais , Proteínas de Bactérias/metabolismo , Análise Química do Sangue/instrumentação , Eletrodos , Glucose/química , Limite de Detecção , Sistemas Automatizados de Assistência Junto ao Leito , Ovinos , Proteínas Virais/metabolismo , alfa-Galactosidase/metabolismo , alfa-Manosidase/metabolismo
9.
Beilstein J Org Chem ; 14: 2520-2528, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30344775

RESUMO

Electron-rich arenes react with aryl and alkyl disulfides in the presence of catalytic amounts of [Ir(dF(CF3)ppy)2(dtbpy)]PF6 and (NH4)2S2O8 under blue light irradiation to yield arylthiols. The reaction proceeds at room temperature and avoids the use of prefunctionalized arenes. Experimental evidence suggests a radical-radical cross coupling mechanism.

10.
J Cell Sci ; 128(23): 4293-305, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26490995

RESUMO

The Rho GTPase Cdc42 regulates key signaling pathways required for multiple cell functions, including maintenance of shape, polarity, proliferation, migration, differentiation and morphogenesis. Although previous studies have shown that Cdc42 is required for proper epithelial development and maintenance, its exact molecular function in kidney development is not well understood. In this study, we define the specific role of Cdc42 during murine kidney epithelial tubulogenesis by deleting it selectively at the initiation of ureteric bud or metanephric mesenchyme development. Deletion in either lineage results in abnormal tubulogenesis, with profound defects in polarity, lumen formation and the actin cytoskeleton. Ultimately, these defects lead to renal failure. Additionally, in vitro analysis of Cdc42-null collecting duct cells shows that Cdc42 controls these processes by regulating the polarity Par complex (Par3-Par6-aPKC-Cdc42) and the cytoskeletal proteins N-Wasp and ezrin. Thus, we conclude that the principal role of Cdc42 in ureteric bud and metanephric mesenchyme development is to regulate epithelial cell polarity and the actin cytoskeleton.


Assuntos
Polaridade Celular/fisiologia , Citoesqueleto/metabolismo , Células Epiteliais/metabolismo , Túbulos Renais/embriologia , Proteína cdc42 de Ligação ao GTP/metabolismo , Animais , Citoesqueleto/genética , Células Epiteliais/citologia , Camundongos , Proteína cdc42 de Ligação ao GTP/genética
11.
Acc Chem Res ; 49(8): 1566-77, 2016 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-27482835

RESUMO

Introducing aryl- and heteroaryl moieties into molecular scaffolds are often key steps in the syntheses of natural products, drugs, or functional materials. A variety of cross-coupling methods have been well established, mainly using transition metal mediated reactions between prefunctionalized substrates and arenes or C-H arylations with functionalization in only one coupling partner. Although highly developed, one drawback of the established sp2-sp2 arylations is the required transition metal catalyst, often in combination with specific ligands and additives. Therefore, photoredox mediated arylation methods have been developed as alternative over the past decade. We begin our survey with visible light photo-Meerwein arylation reactions, which allow C-H arylation of heteroarenes, enones, alkenes, and alkynes with organic dyes, such as eosin Y, as the photocatalyst. A good number of examples from different groups illustrate the broad application of the reaction in synthetic transformations. While initially only photo-Meerwein arylation-elimination processes were reported, the reaction was later extended to photo-Meerwein arylation-addition reactions giving access to the photoinduced three component synthesis of amides and esters from alkenes, aryl diazonium salts, nitriles or formamides, respectively. Other substrates with redox-active leaving groups have been explored in photocatalyzed arylation reactions, such as diaryliodonium and triarylsulfonium salts, and arylsulfonyl chlorides. We discus some examples with their scope and limitations. The scope of arylation reagents for photoredox reactions was extended to aryl halides. The challenge here is the extremely negative reduction potential of aryl halides in the initial electron transfer step compared to, e.g., aryl diazonium or diaryliodonium salts. In order to reach reduction potentials over -2.0 V vs SCE two consecutive photoinduced electron transfer steps were used. The intermediary formed colored radical anion of the organic dye perylenediimide is excited by a second photon allowing the one electron reduction of acceptor substituted aryl chlorides. The radical anion of the aryl halide fragments under the loss of a halide ion and the aryl radical undergoes C-H arylation with biologically important pyrrole derivatives or adds to a double bond. Rhodamine 6G as an organic photocatalyst allows an even higher degree of control of the reaction. The dye is photoreduced in the presence of an amine donor under irradiation with green light (e.g., 530 nm), yielding its radical anion, which is a mild reducing reagent. The hypsochromic shift of the absorption of the rhodamine 6G radical anion toward blue region of the visible light spectrum allows its selective excitation using blue light (e.g., 455 nm). The excited radical anion is highly reducing and able to activate even bromoanisole for C-H arylation reactions, although only in moderate yield. Photoredox catalytic C-H arylation reactions are valuable alternatives to metal catalyzed reactions. They have an excellent functional group tolerance, could potentially avoid metal containing catalysts, and use visible light as a traceless reagent for the activation of arylating reagents.

12.
Org Biomol Chem ; 15(12): 2536-2540, 2017 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-28256669

RESUMO

Photochemical N-formylation of amines was performed under simple and mild reaction conditions. Amines are common electron donors in reductive photocatalysis, which then typically decompose after donating an electron to the photocatalyst. We have found that these oxidized amines can be utilized to give N-formamides in the presence of air without additional formylating agents. The reaction proceeds via the in situ formation of enamines. Oxygen (air) is necessary for the reaction to occur as it regenerates the photocatalyst forming superoxide radical anions as crucial intermediates involved in the reaction.

13.
Anal Chem ; 88(8): 4248-53, 2016 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-26990833

RESUMO

Glycosidases are essential enzymes that cleave glycoside bonds. The presence of glycosidases have been widely used to detect pathogens, label cells/tissues, and report specific diseases. We have developed a rapid electrochemical assay to detect glycosidases. Exposure of electrochemically inactive substrates to glycosidases releases glucose, which can be measured easily using an electrochemical cell. Five different glycosidases were detected rapidly within 1 h using disposable electrodes. This assay could readily be incorporated into repurposed glucose meters to rapidly detect glycosidases, which in turn could be useful to report the presence of a pathogen or illness.


Assuntos
Técnicas Eletroquímicas/métodos , Glicosídeo Hidrolases/urina , Equipamentos Descartáveis , Técnicas Eletroquímicas/instrumentação , Eletrodos , Glucose/análise , Glucose/metabolismo , Glicosídeo Hidrolases/metabolismo , Humanos , Fatores de Tempo
14.
Chemistry ; 21(45): 15914-8, 2015 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-26404672

RESUMO

A mild and efficient one-pot method has been developed for the stereoselective synthesis of structurally diverse novel iminosugar C-alkynylglycosides. The generality of this methodology has been demonstrated with a wide variety of amines and copper acetylides. This one-pot method has been exploited in the synthesis of new class of DNA cross-linking agents, polyhydroxy 1-vinyl-tetrahydroindolizine derivatives.

15.
Development ; 138(7): 1247-57, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21350016

RESUMO

The mammalian kidney is composed of thousands of individual epithelial tubules known as nephrons. Deficits in nephron number are associated with myriad diseases ranging from complete organ failure to congenital hypertension. A balance between differentiation and maintenance of a mesenchymal progenitor cell population determines the final number of nephrons. How this balance is struck is poorly understood. Previous studies have suggested that Wnt9b/ß-catenin signaling induced differentiation (mesenchymal-to-epithelial transition) in a subset of the progenitors but needed to be repressed in the remaining progenitors to keep them in the undifferentiated state. Here, we report that Wnt9b/ß-catenin signaling is active in the progenitors and is required for their renewal/proliferation. Using a combination of approaches, we have revealed a mechanism through which cells receiving the same Wnt9b/ß-catenin signal can respond in distinct ways (proliferate versus differentiate) depending on the cellular environment in which the signal is received. Interpretation of the signal is dependent, at least in part, on the activity of the transcription factor Six2. Six2-positive cells that receive the Wnt9b signal are maintained as progenitors whereas cells with reduced levels of Six2 are induced to differentiate by Wnt9b. Using this simple mechanism, the kidney is able to balance progenitor cell expansion and differentiation insuring proper nephron endowment. These findings provide novel insights into the molecular mechanisms that regulate progenitor cell differentiation during normal and pathological conditions.


Assuntos
Rim/embriologia , Néfrons/embriologia , Transdução de Sinais/fisiologia , Células-Tronco/metabolismo , Proteínas Wnt/metabolismo , Animais , Diferenciação Celular , Proliferação de Células , Imunoprecipitação da Cromatina , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Imuno-Histoquímica , Hibridização In Situ , Rim/citologia , Rim/metabolismo , Camundongos , Néfrons/citologia , Néfrons/metabolismo , Organogênese/fisiologia , Células-Tronco/citologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas Wnt/genética , beta Catenina/genética , beta Catenina/metabolismo
16.
Pediatr Blood Cancer ; 61(2): 198-205, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24115727

RESUMO

BACKGROUND: The Yes-associated-protein-1 (YAP1) is a novel, direct regulator of stem cell genes both in development and cancer. FAT4 is an upstream regulator that induces YAP1 cytosolic sequestering by phosphorylation (p-Ser 127) and therefore inhibits YAP1-dependent cellular proliferation. We hypothesized that loss of FAT4 signaling would result in expansion of the nephron progenitor population in kidney development and that YAP1 subcellular localization would be dysregulated in Wilms tumor (WT), an embryonal malignancy that retains gene expression profiles and histologic features reminiscent of the embryonic kidney. METHODS: Fetal kidneys from Fat4(-/-) mice were harvested at e18.5 and markers of nephron progenitors were investigated using immunohistochemical analysis. To examine YAP1 subcellular localization in WT, a primary WT cell line (VUWT30) was analyzed by immunofluorescence. Forty WT specimens evenly distributed between favorable and unfavorable histology (n = 20 each), and treatment failure or success (n = 20 each) was analyzed for total and phosphorylated YAP1 using immunohistochemistry and Western blot. RESULTS: Fat4(-/-) mouse fetal kidneys exhibit nuclear YAP1 with increased proliferation and expansion of nephron progenitor cells. In contrast to kidney development, subcellular localization of YAP1 is dysregulated in WT, with a preponderance of nuclear p-YAP1. By Western blot, median p-YAP1 quantity was 5.2-fold greater in unfavorable histology WT (P = 0.05). CONCLUSIONS: Fetal kidneys in Fat4(-/-) mice exhibit a phenotype reminiscent of nephrogenic rests, a WT precursor lesion. In WT, YAP1 subcellular localization is dysregulated and p-YAP1 accumulation is a novel biomarker of unfavorable histology.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Embrião de Mamíferos/patologia , Regulação da Expressão Gênica no Desenvolvimento , Rim/embriologia , Rim/patologia , Fosfoproteínas/metabolismo , Fosfoproteínas/fisiologia , Tumor de Wilms/patologia , Animais , Western Blotting , Proteínas de Ciclo Celular , Núcleo Celular/metabolismo , Núcleo Celular/patologia , Proliferação de Células , Células Cultivadas , Pré-Escolar , Embrião de Mamíferos/metabolismo , Feminino , Células HeLa , Humanos , Técnicas Imunoenzimáticas , Rim/metabolismo , Neoplasias Renais/metabolismo , Neoplasias Renais/patologia , Masculino , Camundongos , Camundongos Knockout , Néfrons/metabolismo , Néfrons/patologia , Fosforilação , Transporte Proteico , Células-Tronco/metabolismo , Células-Tronco/patologia , Frações Subcelulares , Fatores de Transcrição , Tumor de Wilms/metabolismo , Proteínas de Sinalização YAP
17.
J Am Soc Nephrol ; 24(6): 873-6, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23578945

RESUMO

For decades we have known that reciprocal inductive interactions between the embryonic ureteric bud and the metanephric mesenchyme are the basis for kidney development. Signals from the mesenchyme promote the branching of the bud, whereas signals from the bud regulate the survival, proliferation, and differentiation of nephron progenitors. Due to the complex nature of the bud-derived signals, progress in identifying these factors has been slow. However, in the last several years, tremendous advances have been made in identifying specific roles for various secreted proteins in nephron progenitor cell development. Here, we briefly review the roles for Fgfs and Wnts in induction of the nephron progenitors.


Assuntos
Néfrons/embriologia , Transdução de Sinais/fisiologia , Nicho de Células-Tronco/fisiologia , Células-Tronco/metabolismo , Ureter/embriologia , Animais , Fatores de Crescimento de Fibroblastos/metabolismo , Humanos , Mesoderma/citologia , Mesoderma/embriologia , Mesoderma/metabolismo , Néfrons/citologia , Néfrons/metabolismo , Células-Tronco/citologia , Ureter/citologia , Ureter/metabolismo , Proteínas Wnt/metabolismo
18.
J Biol Chem ; 287(23): 19622-30, 2012 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-22514284

RESUMO

Concerted actions of estrogen and progesterone via their cognate receptors orchestrate changes in the uterine tissue, regulating implantation during early pregnancy. The uterine stromal cells undergo steroid-dependent differentiation into morphologically and functionally distinct decidual cells, which support embryonic growth and survival. The hormone-regulated pathways underlying this unique cellular transformation are not fully understood. Previous studies in the mouse revealed that, following embryo attachment, de novo synthesis of estrogen by the decidual cells is critical for stromal differentiation. In this study we report that Fos-related antigen 1 (FRA-1), a member of the Fos family of transcription factors, is a downstream target of regulation by intrauterine estrogen. FRA-1 expression was localized in the differentiating uterine stromal cells surrounding the implanted embryo. Attenuation of estrogen receptor α (Esr1) expression by siRNA mediated silencing in primary uterine stromal cells suppressed FRA-1 expression. Furthermore, chromatin immunoprecipitation demonstrated direct recruitment of ESR1 to an estrogen response element in the Fra-1 promoter. Down-regulation of Fra-1 expression during in vitro decidualization blocked stromal differentiation and resulted in a marked decrease in stromal cell migration. Interestingly, FRA-1 controls the expression of matrix metalloproteinases MMP9 and MMP13, which are critical modulators of stromal extracellular matrix remodeling. Collectively, these results suggest that FRA-1, induced in response to estrogen signaling via ESR1, is a key regulator of stromal differentiation and remodeling during early pregnancy.


Assuntos
Diferenciação Celular/fisiologia , Receptor alfa de Estrogênio/metabolismo , Estrogênios/metabolismo , Gravidez/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Útero/metabolismo , Animais , Movimento Celular/fisiologia , Implantação do Embrião/fisiologia , Receptor alfa de Estrogênio/genética , Feminino , Regulação Enzimológica da Expressão Gênica/fisiologia , Masculino , Metaloproteinase 13 da Matriz/biossíntese , Metaloproteinase 9 da Matriz/biossíntese , Camundongos , Células Estromais/citologia , Células Estromais/metabolismo , Útero/citologia
19.
Chemphyschem ; 14(17): 4010-21, 2013 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-24259302

RESUMO

A new design for a quasi-solid-state Forster resonance energy transfer (FRET) enabled solar cell with unattached Lucifer yellow (LY) dye molecules as donors and CdS/CdSe quantum dots (QDs) tethered to titania (TiO2 ) as acceptors is presented. The Forster radius is experimentally determined to be 5.29 nm. Sequential energy transfer from the LY dye to the QDs and electron transfer from the QDs to TiO2 is followed by fluorescence quenching and electron lifetime studies. Cells with a donor-acceptor architecture (TiO2 /CdS/CdSe/ZnS-LY/S(2-)-multi-walled carbon nanotubes) show a maximum incident photon-to-current conversion efficiency of 53 % at 530 nm. This is the highest efficiency among Ru-dye free FRET-enabled quantum dot solar cells (QDSCs), and is much higher than the donor or acceptor-only cells. The FRET-enhanced solar cell performance over the majority of the visible spectrum paves the way to harnessing the untapped potential of the LY dye as an energy relay fluorophore for the entire gamut of dye sensitized, organic, or hybrid solar cells.

20.
J Phys Chem A ; 117(28): 5802-11, 2013 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-23796026

RESUMO

A Cu(II)-malonate complex with formula {(C5H6N2Cl)12[Cu(1)(C3H2O4)2][Cu(2)(C3H2O4)2(H2O)2][Cu(4)(C3H2O4)2][Cu(3)(C3H2O4)2(H2O)2](ClO4)4}n (1) [C5H6N2Cl = protonated 2-amino-5-chloropyridine, C3H4O4 = malonic acid, ClO4(-) = perchlorate] has been synthesized from purely aqueous media simple by mixing the reactants in their stoichiometric ratio, and its crystal structure has been determined by single-crystal X-ray diffraction. In 1, copper(II) malonate units form infinite 1D polymeric chains, which are interlinked by hydrogen bonds to generate 2D sheets. These 2D sheets are joined side by side primarily by various hydrogen bonds to form a 3D structure. A multitude of salt bridges are formed in this structure, connecting the protonated 2-amino-5-chloropyridines and the malonate ligands of the polymeric polyanion. Examining this characteristic of the solid-state architecture, we noticed several salt-bridge (sb)···π interactions and an unexplored interaction between the lone pair (lp) of one malonate oxygen atom and a planar salt bridge. The combination of this interaction with various other weak intermolecular forces results in a remarkably extended supramolecular network combining a wide variety of interactions involving π-systems (Cl···π, π···π) and salt bridges (sb···π and lp···sb). We describe the energetic and geometric features of this lone pair-salt-bridge interaction and explore its impact on the resultant supramolecular organization using theoretical DFT-D3 calculations.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA