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The separation of CO/N2 mixtures is a challenging problem in the petrochemical sector due to the very similar physical properties of these two molecules, such as size, molecular weight and boiling point. To solve this and other challenging gas separations, one requires a holistic approach. The complexity of a screening exercise for adsorption-based separations arises from the multitude of existing porous materials, including metal-organic frameworks. Besides, the multivariate nature of the performance criteria that needs to be considered when designing an optimal adsorbent and a separation process - i.e. an optimal material requires fulfillment of several criteria simultaneously - makes the screening challenging. To address this, we have developed a multi-scale approach combining high-throughput molecular simulation screening, data mining and advanced visualization, as well as process system modelling, backed up by experimental validation. We have applied our recent advances in the engineering of porous materials' morphology to develop advanced monolithic structures. These conformed, shaped monoliths can be used readily in industrial applications, bringing a valuable strategy for the development of advanced materials. This toolbox is flexible enough to be applied to multiple adsorption-based gas separation applications.
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A new approach for room-temperature 17O enrichment of zeolites reveals a surprisingly dynamic and labile framework, where rapid and reversible bond breaking takes place. 17O NMR spectroscopy shows that although O sites in both framework Si-O-Al and Si-O-Si linkages are enriched simply on exposure to H217O(l), the enrichment of Si-O-Al species is more rapid, with a more uniform framework enrichment observed at longer durations. We demonstrate that this unexpected enrichment can be observed for two different framework topologies and for Na-exchanged (i.e., nonacidic) zeolites, as well as their protonic forms, confirming that the Brønsted acid proton is not necessary for isotopic exchange into the framework. This work not only offers new opportunities for structural characterization of these chemically and industrially important materials using NMR spectroscopy but suggests that further investigation of the rate and position of enrichment in zeolite frameworks could provide new insight into their chemical reactivity and their stability in aqueous-based applications such as ion exchange and catalysis.
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BACKGROUND & AIMS: ZBP-89 (also ZNF148 or Zfp148) is a butyrate-inducible zinc finger transcription factor that binds to GC-rich DNA elements. Deletion of the N-terminal domain is sufficient to increase mucosal susceptibility to chemical injury and inflammation. We investigated whether conditional deletion of ZBP-89 from the intestinal and colonic epithelium of mice increases their susceptibility to pathogens such as Salmonella typhimurium. METHODS: We generated mice with a conditional null allele of Zfp148 (ZBP-89(FL/FL)) using homologous recombination to flank Zfp148 with LoxP sites (ZBP-89(FL/FL)), and then bred the resulting mice with those that express VillinCre. We used microarray analysis to compare gene expression patterns in colonic mucosa between ZBP-89(ΔInt) and C57BL/6 wild-type mice (controls). Mice were gavaged with 2 isogenic strains of S. typhimurium after administration of streptomycin. RESULTS: Microarray analysis revealed that the colonic mucosa of ZBP-89(ΔInt) mice had reduced levels of tryptophan hydroxylase 1 (Tph1) messenger RNA, encoding the rate-limiting enzyme in enterochromaffin cell serotonin (5-hydroxytryptamine [5HT]) biosynthesis. DNA affinity precipitation demonstrated direct binding of ZBP-89 to the mouse Tph1 promoter, which was required for its basal and butyrate-inducible expression. ZBP-89(ΔInt) mice did not increase mucosal levels of 5HT in response to S. typhimurium infection, and succumbed to the infection 2 days before control mice. The ΔhilA isogenic mutant of S. typhimurium lacks this butyrate-regulated locus and stimulated, rather than suppressed, expression of Tph1 approximately 50-fold in control, but not ZBP-89(ΔInt), mice, correlating with fecal levels of butyrate. CONCLUSIONS: ZBP-89 is required for butyrate-induced expression of the Tph1 gene and subsequent production of 5HT in response to bacterial infection in mice. Reductions in epithelial ZBP-89 increase susceptibility to colitis and sepsis after infection with S. typhimurium, partly because of reduced induction of 5HT production in response to butyrate and decreased secretion of antimicrobial peptides.
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Proteínas de Unión al ADN/fisiología , Mucosa Intestinal/inmunología , ARN Mensajero/análisis , Infecciones por Salmonella/inmunología , Serotonina/biosíntesis , Factores de Transcripción/fisiología , Triptófano Hidroxilasa/fisiología , Animales , Butiratos/inmunología , Colitis/inmunología , Proteínas de Unión al ADN/genética , Células Enterocromafines/inmunología , Ratones , Ratones Transgénicos , Regiones Promotoras Genéticas , Salmonella typhimurium , Serotonina/inmunología , Factores de Transcripción/genéticaRESUMEN
The first square planar rhodium(I) complexes containing the 6,6'-dihydroxy-2,2'-bipyridine ligand have been prepared. The complexes form molecular wires in the solid state and are active catalysts for the carbonylation of methyl acetate.
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The use of ligands with proximate hydrogen bonding substituents in the oxidation of platinum(II) dimethyl complexes with H2O2 leads to the exclusive formation of an unusual cis-dihydroxo platinum(IV) complex, which can dehydrate to form a trinuclear metalla-azacrown complex.
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Gastrin is secreted from neuroendocrine cells residing in the adult antrum called G cells, but constitutively low levels are also expressed in the duodenum and fetal pancreas. Gastrin normally regulates gastric acid secretion by stimulating the proliferation of enterochromaffin-like cells and the release of histamine. Gastrin and progastrin forms are expressed in a number of pathological conditions and malignancies. However, the DNA regulatory elements in the human versus the mouse gastrin promoters differ suggesting differences in their transcriptional control. Thus, we describe here the expression of the human gastrin gene using a bacterial artificial chromosome (BAC) in the antral and duodenal cells of gastrin null mice. All 5 founder lines expressed the 253 kb human gastrin BAC. hGasBAC transgenic mice were bred onto a gastrin null background so that the levels of human gastrin peptide could be analyzed by immunohistochemistry and radioimmunoassay without detecting endogenous mouse gastrin. We have shown previously that chronically elevated gastrin levels suppress somatostatin. Indeed, infusion of amidated rat gastrin depressed somatostatin levels, stimulated gastric acid secretion and an increase in the numbers of G cells in the antrum and duodenum. In conclusion, human gastrin was expressed in mouse enteroendocrine cells and was regulated by somatostatin. This mouse model provides a unique opportunity to study regulation of the human gastrin promoter in vivo by somatostatin and possibly other extracellular regulators contributing to our understanding of the mechanisms involved in transcriptional control of the human gene.
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Gastrinas/genética , Animales , Secuencia de Bases , Cromosomas Artificiales Bacterianos/genética , Cartilla de ADN/genética , Duodeno/citología , Duodeno/efectos de los fármacos , Duodeno/metabolismo , Células Secretoras de Gastrina/efectos de los fármacos , Células Secretoras de Gastrina/metabolismo , Gastrinas/deficiencia , Gastrinas/metabolismo , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Antro Pilórico/citología , Antro Pilórico/efectos de los fármacos , Antro Pilórico/metabolismo , Somatostatina/farmacología , Activación Transcripcional/efectos de los fármacosRESUMEN
Birth defects surveillance systems collect population-based birth defects data from multiple sources to track trends in prevalence, identify risk factors, refer affected families to services, and evaluate prevention efforts. Strong state and federal public health and legal mandates are in place to govern the collection and use of these data. Despite the prima facie appeal of "opt-in" and similar strategies to those who view data collection as a threat to privacy, the use of these strategies in lieu of population-based surveillance can severely limit the ability of public health agencies to accurately access the health status of a group within a defined geographical area. With the need for population-based data central to their mission, birth defects programs around the country take their data stewardship role seriously, recognizing both moral and legal obligations to protect the data by employing numerous safeguards. Birth defects surveillance systems are shaped by the needs of the community they are designed to serve, with the goal of preventing birth defects or alleviating the burdens associated with them.
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Seguridad Computacional , Anomalías Congénitas/epidemiología , Recolección de Datos/métodos , Vigilancia de la Población , Adulto , Confidencialidad , Anomalías Congénitas/prevención & control , Recolección de Datos/estadística & datos numéricos , Femenino , Humanos , Recién Nacido , Embarazo , Prevalencia , Registros , Estados Unidos/epidemiologíaRESUMEN
The acid-catalyzed formation of carbon-carbon bonds from C1 precursors via CO insertion into chemisorbed methyl groups occurs selectively within eight-membered ring (8-MR) zeolite channels. This elementary step controls catalytic carbonylation rates of dimethyl ether (DME) to methyl acetate. The number of O-H groups within 8-MR channels was measured by rigorous deconvolution of the infrared bands for O-H groups in cation-exchanged and acid forms of mordenite (M,H-MOR) and ferrierite (H-FER) after adsorption of basic probe molecules of varying size. DME carbonylation rates are proportional to the number of O-H groups within 8-MR channels. Na+ cations selectively replaced protons within 8-MR channels and led to a disproportionate decrease in carbonylation turnover rates (per total H+). These conclusions are consistent with the low or undetectable rates of carbonylation on zeolites without 8-MR channels (H-BEA, H-FAU, H-MFI). Such specificity of methyl reactivity upon confinement within small channels appears to be unprecedented in catalysis by microporous solids, which typically select reactions by size exclusion of bulkier transition states.
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A member of the Tennessee state legislature recently proposed a bill that would mandate all newborn infants to undergo pulse oximetry screening for the purpose of identifying those with critical structural heart disease before discharge home. The Tennessee Task Force on Screening Newborn Infants for Critical Congenital Heart Defects was convened on September 29, 2005. This group reviewed the current medical literature on this topic, as well as data obtained from the Tennessee Department of Health, and debated the merits and potential detriments of a statewide screening program. The estimated incidence of critical congenital heart disease is 170 in 100,000 live births, and of those, 60 in 100,000 infants have ductal-dependent left-sided obstructive lesions with the potential of presentation by shock or death if the diagnosis is missed. Of the latter group, the diagnosis is missed in approximately 9 in 100,000 by fetal ultrasound assessment and discharge examination and might be identified by a screening program. Identification of the missed diagnosis in these infants before discharge could spare many of them death or neurologic sequelae. Four major studies using pulse oximetry screening were analyzed, and when data were restricted to critical left-sided obstructive lesions, sensitivity values of 0% to 50% and false-positive rates of between 0.01% and 12% were found in asymptomatic populations. Because of this variability and other considerations, a meaningful cost/benefit analysis could not be performed. It was the consensus of the task force to provide a recommendation to the legislature that mandatory screening not be implemented at this time. In addition, we determined that a very large, prospective, perhaps multistate study is needed to define the sensitivity and false-positive rates of lower-limb pulse oximetry screening in the asymptomatic newborn population and that there needs to be continued partnering between the medical community, parents, and local, state, and national governments in decisions regarding mandated medical care.
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Directrices para la Planificación en Salud , Cardiopatías Congénitas/diagnóstico , Tamizaje Neonatal/legislación & jurisprudencia , Tamizaje Neonatal/estadística & datos numéricos , Oximetría/estadística & datos numéricos , Comités Consultivos , Reacciones Falso Positivas , Política de Salud , Cardiopatías Congénitas/epidemiología , Humanos , Incidencia , Recién Nacido , Formulación de Políticas , Sensibilidad y Especificidad , Tennessee/epidemiologíaRESUMEN
ZNF148 (ZBP-89, Zfp148) is a multifunctional transcription factor expressed at low levels in most tissues. When overexpressed in gastrointestinal cancer cell lines, ZNF148 inhibits cellular proliferation and induces apoptosis. We sought to determine whether intestinal ZNF148 overexpression would abrogate adenoma development in the ApcMin/+ mouse, i.e., whether ZNF148 is a tumor suppressor. The 13-kb villin promoter was spliced upstream of the ZNF148 cDNA to generate transgenic villin-ZNF148 (ZNF148TgVZ) mice. Intestinal mucosal ZNF148 expression was elevated in four of five ZNF148(TgVZ) lineages and correlated with increased caspase-3 expression and activation. In addition, DNA fragmentation was increased in ZNF148TgVZ mice relative to wild-type littermates. These results suggested that increased intestinal ZNF148 expression induces apoptosis. ZNF148TgVZ mice were crossed with ApcMin/+ mice to assess the biological significance of intestinal ZNF148 overexpression. The presence of the ZNF148TgVZ allele in ApcMin/+ mice correlated with reduced gastrointestinal bleeding at 5 weeks, a 50% reduction in adenoma burden at 20-22 weeks, and prolonged survival (median survival of 33.5 days vs. 21.5 days), relative to nontransgenic littermates. These data suggest that enhanced ZNF148 expression activates intestinal apoptosis and thereby mitigates disease burden in ApcMin/+ mice. They also suggest that ZNF148 is a therapeutic target to inhibit colon cancer development.
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Proteína de la Poliposis Adenomatosa del Colon/metabolismo , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/fisiología , Mucosa Intestinal/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción/fisiología , Adenoma/metabolismo , Adenoma/mortalidad , Proteína de la Poliposis Adenomatosa del Colon/genética , Alelos , Animales , Apoptosis/fisiología , Cruzamientos Genéticos , Enfermedades Gastrointestinales/genética , Enfermedades Gastrointestinales/mortalidad , Enfermedades Gastrointestinales/prevención & control , Hemorragia/genética , Hemorragia/mortalidad , Hemorragia/prevención & control , Neoplasias Intestinales/metabolismo , Neoplasias Intestinales/mortalidad , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Linaje , Análisis de Supervivencia , Carga Tumoral/genética , Proteínas Supresoras de Tumor/metabolismo , Proteínas Supresoras de Tumor/fisiologíaRESUMEN
BACKGROUND & AIMS: Histone deacetylase inhibitors (HDACi) induce growth arrest, apoptosis, and differentiation, particularly in colon cancer cells where they are potential chemopreventive agents. HDACi induction of the cyclin-dependent kinase inhibitor p21(waf1) has been shown to require ataxia-telangiectasia mutated (ATM). Nevertheless, how ATM participates in p21(waf1) gene expression has not been defined. METHODS: In vivo protein complexes forming in response to butyrate were studied using co-immunoprecipitation and mass spectroscopy. DNA elements in the p21(waf1) promoter were analyzed in vivo by chromatin immunoprecipitation and in vitro DNA affinity precipitation assays. The expression of p21(waf1) was analyzed by immunoblots and reporter assays. RESULTS: Reduction of ZBP-89 or ATM with small interfering RNAs blocked HDACi-induced p21(waf1) expression. Chromatin immunoprecipitation and DNA affinity precipitation assays showed that both ZBP-89 and ATM are recruited to the GC-rich DNA elements of the p21(waf1) promoter with HDACi treatment. Co-immunoprecipitation revealed that ATM associates with ZBP-89 in an HDACi-dependent manner. Serial deletions revealed that ATM interacts with both the N-terminal and DNA binding domains of ZBP-89. Moreover, we found that immunodepletion of ZBP-89 prevented recruitment of ATM to the p21(waf1) promoter in vitro. Silencing of ZBP-89 expression blocked HDACi-induced phosphorylation of ATM(Ser1981) and p53(Ser15). ATM(Ser1981) phosphorylation in the colons of mutant mice expressing an N-terminally truncated form of ZBP-89 was not observed after ingestion of dextran sodium sulfate and correlated with exacerbation of the mucosal injury. CONCLUSIONS: ZBP-89 interacts with ATM in a butyrate-dependent manner and is essential for colonic homeostasis in the setting of acute mucosal injury.
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Proteínas de Ciclo Celular/metabolismo , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Expresión Génica , Mucosa Intestinal/metabolismo , Mutación , Proteínas Serina-Treonina Quinasas/metabolismo , ARN/genética , Factores de Transcripción/genética , Proteínas Supresoras de Tumor/metabolismo , Animales , Proteínas de la Ataxia Telangiectasia Mutada , Línea Celular Tumoral , Colitis/inducido químicamente , Colitis/metabolismo , Colitis/patología , Sulfato de Dextran/toxicidad , Histona Desacetilasas/farmacología , Humanos , Inmunoprecipitación , Técnicas In Vitro , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/patología , Ratones , Microscopía Fluorescente , Factores de Transcripción/metabolismoRESUMEN
Alternative splicing enables expression of functionally diverse protein isoforms. The structural and functional complexity of zinc-finger transcription factor ZBP-89 suggests that it may be among the class of alternatively spliced genes. We identified a human ZBP-89 splice isoform (ZBP-89(DeltaN)), which lacks amino terminal residues 1-127 of the full-length protein (ZBP-89(FL)). ZBP-89(DeltaN) mRNA was co-expressed with its ZBP-89(FL) cognate in gastrointestinal cell lines and tissues. Similarly, ZBP-89(DeltaN) protein was expressed. To define its function in vivo, we generated ZBP-89(DeltaN) knock-in mice by targeting exon 4 that encodes the amino terminus. Homozygous ZBP-89(DeltaN) mice, expressing only ZBP-89(DeltaN) protein, experienced growth delay, reduced viability and increased susceptibility to dextran sodium sulfate colitis. We conclude that ZBP-89(DeltaN) antagonizes ZBP-89(FL) function and that over-expression of the truncated isoform disrupts gastrointestinal homeostasis.
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Colitis/etiología , Proteínas de Unión al ADN/metabolismo , Factores de Transcripción/metabolismo , Empalme Alternativo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Colitis/inducido químicamente , Colitis/patología , Colon/metabolismo , Proteínas de Unión al ADN/análisis , Proteínas de Unión al ADN/genética , Sulfato de Dextran , Exones , Femenino , Marcación de Gen , Trastornos del Crecimiento/etiología , Humanos , Masculino , Ratones , Datos de Secuencia Molecular , Pan troglodytes , Regiones Promotoras Genéticas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Análisis de Supervivencia , Factores de Transcripción/análisis , Factores de Transcripción/genéticaRESUMEN
p53 has recently been identified as a downstream target of ZBP-89, a zinc finger transcription factor. ZBP-89 promotes growth arrest through stabilization of the p53 protein. The aim of this study is to determine the status of the p53 gene in recurrent human hepatocellular carcinoma (HCC) and test the link between the expression of ZBP-89 and the p53 gene. The results showed that mutations in the p53 gene were frequently detected in recurrent HCC. The interval between surgical resection and the recurrence of HCC was significantly longer in patients with the wild-type p53 gene than those with mutations, strongly suggesting a pathological role for the mutant p53 gene in HCC recurrence. Among those positive for the p53 protein, nearly 85% (18 of 21) showed nuclear localization of the p53 protein while only about 14% (3 of 21) were positive for the p53 protein in the cytoplasm. ZBP-89 co-localized with p53 in the nucleus in about 67% (12 of 18) of all cases positive for the nuclear p53 protein, suggesting that ZBP-89 may play a role in the nuclear accumulation of the p53 protein in a subset of recurrent HCC. With accumulation of p53 protein in the nucleus, tumor cells undergo apoptosis and thus are more susceptible to radiotherapy and chemotherapy. Therefore, co-localization of p53 protein with ZBP-89 may define a subgroup of recurrent HCC that is more sensitive to treatment.