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1.
BJOG ; 128(9): 1497-1502, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33629515

RESUMEN

OBJECTIVE: To investigate whether antenatal corticosteroid therapy improves neonatal and maternal outcomes in late preterm delivery. DESIGN: Population-based retrospective study. SETTING: The linkages of Taiwan's National Health Insurance Research Database, National Birth Reporting Database, and the Taiwan Maternal and Child Health Database. POPULATION: All births at risk for late preterm deliveries in Taiwan between 2004 and 2011. METHODS: For every birth at risk for late preterm delivery, five controls randomly matched by maternal and gestational ages and birthweight were included. A conditional logistic regression analysis was applied for risk estimation, with births without corticosteroids as the reference group. Odds ratios were adjusted for caesarean section, parity, sex, gestational hypertension and gestational diabetes mellitus. MAIN OUTCOME MEASURES: Neonatal outcomes, maternal outcomes and the utilisation of healthcare services. RESULTS: The outcomes of 5745 women treated with corticosteroids between 34+0  weeks and 36+6  weeks of gestation were compared with those of 28 135 untreated controls. Compared with the controls, births from women administered corticosteroids reduced the need for continuous positive airway pressure, the number of neonatal intensive care unit admission, and the need for glucose administration, as well as the risk of neonatal respiratory distress, but increased the risk of neonatal sepsis and the number of outpatient visits. CONCLUSIONS: Antenatal corticosteroid therapy in women at risk of late preterm delivery may significantly reduce the need for respiratory support and glucose supply, and respiratory complication risk in neonates. TWEETABLE ABSTRACT: Antenatal corticosteroids in late preterm delivery reduced the risk of neonatal respiratory complications in Taiwan.


Asunto(s)
Corticoesteroides/administración & dosificación , Nacimiento Prematuro/tratamiento farmacológico , Síndrome de Dificultad Respiratoria del Recién Nacido/prevención & control , Corticoesteroides/efectos adversos , Adulto , Estudios de Casos y Controles , Bases de Datos Factuales , Femenino , Humanos , Recién Nacido , Masculino , Sepsis Neonatal/epidemiología , Embarazo , Nacimiento Prematuro/epidemiología , Síndrome de Dificultad Respiratoria del Recién Nacido/epidemiología , Estudios Retrospectivos , Medición de Riesgo , Taiwán/epidemiología
2.
Mucosal Immunol ; 12(4): 980-989, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31076664

RESUMEN

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces cell apoptosis by transducing apoptosis signals. Recently, accumulating evidence demonstrated that TRAIL regulates autoimmune inflammation and immune cell homeostasis in several autoimmune animal models, suggesting a novel immunoregulatory role of TRAIL in autoimmune diseases. However, the impact of TRAIL in inflammatory bowel disease is yet undefined. This study is to address the therapeutic effects and immunoregulatory role of TRAIL in autoimmune gut inflammation. We demonstrated herein that TRAIL significantly suppressed gut inflammation and reduced the severity of colitis in a dextran sodium sulfate (DSS)-induced colitis model. Suppression of gut inflammation was not due to induction of apoptosis in colonic T cells, dendritic cells, or epithelium cells by TRAIL. In contrast, TRAIL directly inhibited activation of colitogenic T cells and development of gut inflammation in an adoptive transfer-induced colitis model. The anti-inflammatory effects of TRAIL on colitis were abolished when T cells from TRAIL receptor (TRAIL-R) knockout mice were adoptively transferred, suggesting that TRAIL regulates autoreactive colitogenic T-cell activation in the development of gut inflammation. Our results demonstrate that TRAIL effectively inhibited colonic T-cell activation and suppressed autoimmune colitis, suggesting a potential therapeutic application of TRAIL in human inflammatory bowel disease.


Asunto(s)
Colitis/etiología , Colitis/metabolismo , Activación de Linfocitos/inmunología , Transducción de Señal , Linfocitos T/inmunología , Linfocitos T/metabolismo , Ligando Inductor de Apoptosis Relacionado con TNF/metabolismo , Animales , Apoptosis , Autoinmunidad , Colitis/patología , Citocinas/metabolismo , Sulfato de Dextran , Modelos Animales de Enfermedad , Humanos , Mediadores de Inflamación/metabolismo , Mucosa Intestinal/inmunología , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patología , Ratones , Ratones Noqueados
3.
Clin Exp Immunol ; 151(3): 383-90, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18190609

RESUMEN

Decoy receptor 3 (DcR3/TR6) is a decoy receptor for the Fas ligand (FasL) and can inhibit FasL-induced apoptosis. It has been reported recently that DcR3 can induce T cell activation via co-stimulation of T cells, suggesting that DcR3 may be involved in the pathophysiology of autoimmune diseases. This study aims to analyse the serum DcR3 in patients with systemic lupus erythematosus (SLE) and to investigate the role of DcR3 in the pathogenesis of SLE. Significantly elevated serum DcR3 was observed in SLE patients, and the mean serum DcR3 level was significantly higher for those with active disease [SLE disease activity index (SLEDAI) >/= 10] compared with that in patients with inactive disease (SLEDAI < 10). In addition to reducing activation-induced cell death in activated T cells via neutralization of the FasL, soluble DcR3-Fc enhanced T cell proliferation and increased interleukin-2 and interferon-gamma production via co-stimulation of T cells. Moreover, enhanced T cell reactivity to DcR3-induced co-stimulation was demonstrated in lymphocytes from patients with SLE, suggesting the elevated serum DcR3 may associate with enhanced T cell activation in vivo. These findings are the first to demonstrate that serum DcR3 concentrations are increased in SLE patients, and this may imply a possible role of DcR3 in the pathogenesis of SLE via enhanced T cell hyperreactivity and reduced apoptosis in activated T cells.


Asunto(s)
Lupus Eritematoso Sistémico/inmunología , Activación de Linfocitos/inmunología , Miembro 6b de Receptores del Factor de Necrosis Tumoral/sangre , Linfocitos T/inmunología , Adulto , Apoptosis/inmunología , Proliferación Celular , Células Cultivadas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Índice de Severidad de la Enfermedad
4.
Genetics ; 136(4): 1307-17, 1994 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8013907

RESUMEN

Seed-borne fungal symbionts (endophytes) provide many cool-season grass species with biological protection from biotic and abiotic stresses. The endophytes are asexual, whereas closely related sexual species of genus Epichloë (Clavicipitales) cause grass choke disease. Perennial ryegrass (Lolium perenne) is a host of two endophyte taxa, LpTG-1 (L. perenne endophyte taxonomic grouping one = Acremonium lolii) and LpTG-2, as well as the choke pathogen, Epichloë typhina (represented by isolate E8). Relationships among these fungi and other Epichloë species were investigated by analysis of gene sequences, DNA polymorphisms and allozymes. The results indicate that LpTG-2 is a heteroploid derived from an interspecific hybrid. The LpTG-2 isolates had two copies each of nine out of ten genes analyzed (the exception being the rRNA gene locus), and the profiles for seven of these were composites of those from E. typhina E8 and A. lolii isolate Lp5. Molecular phylogenetic analysis grouped the two beta-tubulin genes of LpTG-2 into separate clades. One (tub2-1) was related to that of E. typhina E8, and the other (tub2-2) to that of A. lolii. The mitochondrial DNA profile of LpTG-2 was similar to that of A. lolii, but its rRNA gene sequence grouped it with E. typhina E8. A proposed model for the evolution of LpTG-2 involves infection of a L. perenne-A. lolii symbiotum by E. typhina, followed by hybridization of the two fungi. Such interspecific hybridization may be a common and important mechanism for genetic variation in Epichloë endophytes.


Asunto(s)
Acremonium/fisiología , Ascomicetos/fisiología , Hibridación Genética , Poaceae/microbiología , Acremonium/enzimología , Acremonium/genética , Secuencia de Aminoácidos , Ascomicetos/enzimología , Ascomicetos/genética , Secuencia de Bases , Cruzamientos Genéticos , Cartilla de ADN , ADN de Hongos , ADN Mitocondrial , Genotipo , Isoenzimas/genética , Datos de Secuencia Molecular , Filogenia , Polimorfismo Genético , ARN Ribosómico/genética , Alineación de Secuencia , Simbiosis , Tubulina (Proteína)/genética
5.
J Biomed Sci ; 3(5): 338-347, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-11725116

RESUMEN

The present study was undertaken to further characterize the nucleus reticularis gigantocellularis (NRGC) of the medulla oblongata in the central processing of nociceptive and cardiovascular signals, and its modulation by met-enkephalin. In Sprague-Dawley rats anesthetized with pentobarbital sodium, we found that all 125 spontaneously active NRGC neurons that responded to noxious stimuli (tail clamp) also exhibited arterial pressure-relatedness. Forty neurons additionally manifested cardiac periodicity that persisted even during nociceptive responses. While maintaining their cardiovascular responsive characteristics, the nociception-related NRGC neuronal activity was blocked, naloxone-reversibly (0.5 mg/kg, i.v.), by morphine (5 mg/kg, i.v.). Microiontophoretically applied met-enkephalin suppressed the responsiveness of NRGC neurons to individually delivered tail clamp or transient hypertension induced by phenylephrine (5 &mgr;g/kg, i.v.). Interestingly, in NRGC neurons that manifested both nociception and arterial pressure relatedness, the preferential reduction in the response to noxious stimuli upon simultaneous elevation in systemic arterial pressure was reversed to one that favored nociception in the presence of met-enkephalin. All actions of met-enkephalin were discernibly blocked by the opioid receptor antagonist, naloxone. Our results suggest that individual NRGC neurons may participate in the processing of both nociceptive and cardiovascular information, or in the coordination of the necessary circulatory supports during nociception. In addition, neuropeptides such as met-enkephalin may exert differential modulation on neuronal responsiveness according to the prevailing physiologic status of the animal. They also showed that NRGC may be a central integrator for pain and cardiovascular-related functions. Copyright 1996 S. Karger AG, Basel

6.
Regul Pept ; 50(3): 247-57, 1994 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-8016409

RESUMEN

We evaluated possible modulation by angiotensin III (AIII) of the interactive effect of noxious stimuli and elevation in systemic arterial pressure on the responsiveness of neurons in the nucleus reticularis gigantocellularis (NRGC) of the medulla oblongata. Combined extracellular single-neuron recording and microiontophoresis were carried out on male, adult Sprague-Dawley rats anesthetized with pentobarbital sodium. The responsiveness of NRGC neurons to nociception (tail clamp) and/or transient hypertension elicited by phenylephrine (5 micrograms/kg, i.v.), in the absence or presence of AIII, was used as the experimental index. Microiontophoretic application of the heptapeptide suppressed the responses of spontaneously active NRGC neurons to individually delivered nociception or hypertension. Interestingly, the preferential reduction in responsiveness to tail clamp upon simultaneous elevation in arterial pressure was reversed to one that favored nociception in the presence of AIII. These actions of the heptapeptide appeared to be receptor-specific, since they were discernibly blocked by its selective antagonist, Ile7-angiotensin III. Our results reveal that neuropeptides such as AIII may differentially modulate neuronal responsiveness according to the prevailing physiologic input(s) to the central nervous system of the animal.


Asunto(s)
Angiotensina III/farmacología , Presión Sanguínea/fisiología , Mapeo Encefálico , Bulbo Raquídeo/fisiología , Neuronas/fisiología , Nociceptores/fisiología , Dolor/fisiopatología , Animales , Presión Sanguínea/efectos de los fármacos , Electrofisiología/métodos , Masculino , Bulbo Raquídeo/efectos de los fármacos , Neuronas/efectos de los fármacos , Nociceptores/efectos de los fármacos , Fenilefrina/farmacología , Ratas , Ratas Sprague-Dawley , Factores de Tiempo
7.
Neurosci Lett ; 165(1-2): 137-40, 1994 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-8015715

RESUMEN

We evaluated the interactive effects of noxious stimuli and elevation in systemic arterial pressure on the responsiveness of spontaneously active neurons in the nucleus reticularis gigantocellularis (NRGC) of male, adult Sprague-Dawley rats anesthetized with pentobarbital sodium. In NRGC neurons that responded to both nociception (tail clamp) and transient hypertension elicited by phenylephrine (5 micrograms/kg, i.v.), the responsiveness to tail clamp was reduced upon simultaneous elevation in arterial pressure. This preferential response pattern did not appear to be affected by the level of anesthesia, since it was demonstrated in animals that were maintained by hourly bolus supplements or continuous infusion of pentobarbital sodium. These data offer a feasible cellular explanation for the documented correlation between elevated nociceptive threshold and hypertension. They also showed that NRGC may be a central integrator for the processing of nociceptive and cardiovascular information.


Asunto(s)
Ganglios Basales/fisiopatología , Hipertensión/fisiopatología , Neuronas/fisiología , Nociceptores/fisiología , Dolor/fisiopatología , Anestesia , Animales , Ganglios Basales/citología , Ganglios Basales/efectos de los fármacos , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Potenciales Evocados/efectos de los fármacos , Potenciales Evocados/fisiología , Masculino , Neuronas/efectos de los fármacos , Nociceptores/efectos de los fármacos , Umbral del Dolor/efectos de los fármacos , Umbral del Dolor/fisiología , Pentobarbital , Fenilefrina/farmacología , Ratas , Ratas Sprague-Dawley
8.
Neurosci Lett ; 159(1-2): 9-12, 1993 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-8264986

RESUMEN

We evaluated the participation of nucleus reticularis gigantocellularis (NRGC), a medullary nucleus that plays an important role in the regulation of nociceptive processes, in the antinociceptive effect of angiotensin III (AIII), a biologically active peptide of the renin-angiotensin system. Adult, male Sprague-Dawley rats anesthetized with pentobarbital sodium (40 mg/kg, i.p., with 10 mg/kg/h i.v. infusion supplement) were used. Bilateral, site-specific microinjection of AIII (80 or 160 pmol) into the NRGC produced a dose-related increase in the latency of tail-flick response to noxious thermal stimuli (50 degrees C hot water). Such an antinociceptive action of AIII was blocked by concomitant administration of the AIII receptor antagonist, Ile7-angiotensin III (Ile7-AIII, 10 nmol). At the neuronal level, microiontophoretic application of AIII suppressed, Ile7-AIII reversibly, the responsiveness of nociception-related neurons in the NRGC to tail-clamping. These results demonstrated that central AIII may elicit antinociception via a process that may at least take place at the NRGC.


Asunto(s)
Analgésicos/farmacología , Angiotensina III/farmacología , Ganglios Basales/fisiología , Angiotensina III/análogos & derivados , Angiotensina III/antagonistas & inhibidores , Animales , Presión Sanguínea/efectos de los fármacos , Iontoforesis , Masculino , Microinyecciones , Neuronas/efectos de los fármacos , Nociceptores/efectos de los fármacos , Dimensión del Dolor/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Técnicas Estereotáxicas
9.
J Formos Med Assoc ; 91(2): 168-73, 1992 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-1364213

RESUMEN

Between 1986 and 1991, 16 selected patients with calculous biliary tract disease (CBTD) underwent side-to-side choledochoduodenostomy (CDS) as an adjunct to either primary (10 patients) or secondary (six patients) choledocholithotomy. Patients selected for adjunctive CDS were those with common bile duct dilatation > or = 1.5 cm in size. All operations were elective procedures. The stoma of the CDS was about 3.0 cm in size, measured directly. There were no operative deaths. There were no early complications related to the CDS procedure itself, except for two (12.5%) wound infections. CDS significantly eliminates bile stasis which is indicated by a fall in both the serum levels of alkaline phosphatase (from 228 +/- 118 to 72 +/- 22 IU/L, p < 0.01) and total bilirubin (from 4.7 +/- 4.7 to 0.9 +/- 0.2 mg/dL, p < 0.01) postoperatively. Late complications (ascending cholangitis or sump syndrome) of CDS or recurrent symptoms of CBTD were not encountered during the average follow-up period of 21 +/- 18 months. From our clinical results, we suggest that adjunctive CDS to choledocholithotomy is a safe and effective procedure in the treatment of selected patients with CBTD.


Asunto(s)
Coledocostomía , Colelitiasis/cirugía , Conducto Colédoco/cirugía , Adulto , Anciano , Humanos , Métodos , Persona de Mediana Edad
10.
Cell Death Dis ; 5: e1109, 2014 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-24603337

RESUMEN

Helicobacter pylori (H. pylori) infection is associated with chronic gastritis, peptic ulcer and gastric cancer. Apoptosis induced by microbial infections is implicated in the pathogenesis of H. pylori infection. Here we show that human gastric epithelial cells sensitized to H. pylori confer susceptibility to TRAIL-mediated apoptosis via modulation of death receptor signaling. Human gastric epithelial cells are intrinsically resistant to TRAIL-mediated apoptosis. The induction of TRAIL sensitivity by H. pylori is dependent on the activation of caspase-8 and its downstream pathway. H. pylori induces caspase-8 activation via enhanced assembly of the TRAIL death-inducing signaling complex (DISC) through downregulation of cellular FLICE-inhibitory protein (FLIP). Overexpression of FLIP abolished the H. pylori-induced TRAIL sensitivity in human gastric epithelial cells. Our study thus demonstrates that H. pylori induces sensitivity to TRAIL apoptosis by regulation of FLIP and assembly of DISC, which initiates caspase activation, resulting in the breakdown of resistance to apoptosis, and provides insight into the pathogenesis of gastric damage in Helicobacter infection. Modulation of host apoptosis signaling by bacterial interaction adds a new dimension to the pathogenesis of Helicobacter.


Asunto(s)
Apoptosis/efectos de los fármacos , Proteína Reguladora de Apoptosis Similar a CASP8 y FADD/metabolismo , Células Epiteliales/efectos de los fármacos , Infecciones por Helicobacter/microbiología , Helicobacter pylori/patogenicidad , Estómago/efectos de los fármacos , Ligando Inductor de Apoptosis Relacionado con TNF/farmacología , Proteína Proapoptótica que Interacciona Mediante Dominios BH3/metabolismo , Caspasa 8/metabolismo , Línea Celular Tumoral , Citocromos c/metabolismo , Proteínas Adaptadoras de Señalización del Receptor del Dominio de Muerte/metabolismo , Relación Dosis-Respuesta a Droga , Activación Enzimática , Células Epiteliales/metabolismo , Células Epiteliales/microbiología , Células Epiteliales/patología , Mucosa Gástrica/metabolismo , Humanos , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Mitocondrias/patología , Proteínas Recombinantes/farmacología , Transducción de Señal/efectos de los fármacos , Estómago/microbiología , Estómago/patología , Factores de Tiempo
12.
Lupus ; 18(8): 676-81, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19502262

RESUMEN

Milk fat globule-EGF factor 8 (MFG-E8) is a molecule implicated in phagocytic clearance of apoptotic cells by bridging between macrophages and apoptotic cells. Defects in MFG-E8 cause lupus-like disease in murine models. The aim of our study is to determine whether genetic variation in MFG-E8 predisposes human to systemic lupus erythematosus (SLE). A case-control study of MFG-E8 genetic polymorphism was performed on 147 SLE patients and 146 non-lupus control subjects. Single nucleotide polymorphisms (SNPs) in the coding sequence of human MFG-E8 gene were investigated. SNPs on MFG-E8 residues 3 (3(Arg or Ser)) and 76 (76(Leu or Met)) did not show genetic linkage. Genetic polymorphism on MFG-E8 residue 76 correlated significantly to SLE. The MFG-E8-76(Met) allele predisposed subjects to SLE in a recessive mode (odds ratio: 2.1, P = 0.020), while carriage of MFG-E8-76(Leu) were negatively associated with SLE. The MFG-E8 genotypic combinations with 3(Ser) and 76(Leu) showed the most pronounced protective effect on SLE when compared to the most predisposing genotype 3(Arg/Arg)-76(Met/Met) (OR: 0.29, P = 0.007). According to our result, MFG-E8 is associated with SLE predisposition in Taiwanese. Our study implicates that the impairment of phagocytic clearance of apoptotic cells through phosphotidylserine-dependent MFG-E8 system may lead to the development of human SLE.


Asunto(s)
Antígenos de Superficie/genética , Predisposición Genética a la Enfermedad , Lupus Eritematoso Sistémico/genética , Proteínas de la Leche/genética , Polimorfismo Genético , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Secuencia de Bases , Estudios de Casos y Controles , Análisis Mutacional de ADN , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Fagocitos/metabolismo , Adulto Joven
13.
Nat Toxins ; 1(3): 171-84, 1992.
Artículo en Inglés | MEDLINE | ID: mdl-1344918

RESUMEN

Acremonium coenophialum Morgan-Jones et W. Gams is a maternally transmitted fungal symbiont (endophyte) of the important forage grass Festuca arundinacea Schreb. (tall fescue), and provides biological protection and enhanced fitness to its host, but its anti-mammalian ergot alkaloids detract from the usefulness of tall fescue as forage for livestock. Molecular genetic techniques and materials are being developed in order to specifically eliminate the gene(s) encoding the first enzyme in ergot alkaloid biosynthesis. These techniques will also facilitate basic studies, such as host-fungus compatibility or biosynthesis of insecticidal alkaloids. Molecular phylogenetics indicate that endophytes related to A. coenophialum have evolved on multiple occasions from strains of Epichloë typhina (Ascomycotina, Clavicipitaceae), for which the sexual cycle is known. These studies also reveal significant diversity among seedborne endophytes in individual grass species. Thus, the endophytes are an important source of biochemical potential and genetic diversity in grass-fungus symbiota.


Asunto(s)
Acremonium/genética , Poaceae/microbiología , Simbiosis , Secuencia de Bases , Evolución Biológica , ADN Complementario/genética , Biblioteca de Genes , Datos de Secuencia Molecular , Transformación Genética
14.
Curr Genet ; 22(5): 399-406, 1992 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-1423727

RESUMEN

Acremonium coenophialum is a mutualistic mycosymbiont and natural agent of biological protection of the widely distributed grass Festuca arundinacea (tall fescue). An electroporative transformation system was developed for A. coenophialum. Segments of DNA 5' to the beta-tubulin gene (tub2) of the closely related ascomycete Epichloë typhina, fused to the Escherichia coli hph gene encoding hygromycin B phosphotransferase, conferred hygromycin resistance when introduced into A. coenophialum by electroporation. The incorporation of the Emericella nidulans trpC terminator greatly increased protoplast germination on selective medium and improved transformation efficiencies 30-200% depending on the plasmid construct. Plasmid pCSN43, which incorporates the trpC controlling elements for hph expression, was also used to transform A. coenophialum. Southern blot analysis of ten pCSN43 transformants indicated the possibility of random integration of this vector into the genome.


Asunto(s)
Acremonium/genética , Poaceae/microbiología , Transformación Genética , Secuencia de Bases , Southern Blotting , ADN de Hongos , Genes Fúngicos , Vectores Genéticos , Datos de Secuencia Molecular , Plásmidos , Simbiosis , Regiones Terminadoras Genéticas , Tubulina (Proteína)/genética
15.
Artículo en Inglés | MEDLINE | ID: mdl-3208574

RESUMEN

For many gram-negative bacteria, whose transformation systems have yet developed, following a two stage manipulation for gene cloning is a common choice. Following this strategy, DNAs are cloned in Escherichia coli, using a mobilizable vector, and the recombinant plasmids conjugally transferred into the original host. In this study, transfer of the broad-host range plasmid pLAFR1 (a 21.6 kb cosmid, TcR, derived from RK2 replicon) from E. coli to Xanthomonas campestris pv. campestris, by the help of plasmid pRK2013, was carried out to optimize the working conditions for gene cloning experiments in this phytopathogenic bacterium. Among several mating procedures tested, the highest frequencies of transfer were found by dropping the mixtures of the donor, helper and recipient cells (at ratios 1:1:10) to a nitrocellulose filter on an agar plate, with all the cells used from the cultures between OD550 0.3 to 0.5. When the non-mucoid mutant P20 was used as the recipient instead of its parental mucoid strain XC11A, 14-fold more transconjugants were obtained. In addition, the plasmid was found to be quite stable in the X. campestris cells. Further experiments showed that pLTA1, which is pLAFR1 with a cloned DNA fragment (4.4 kb) encoding alpha-amylase activity from XC11A, was not only maintained stably but also found to contribute a 8.3-fold over-production of enzyme activity to the transconjugant cells. From these studies, it has been demonstrated that cosmid pLAFR1 and the non-mucoid mutant P20 together provide a suitable vector/host system for cloning genes in X. campestris.


Asunto(s)
Cósmidos , Xanthomonas/genética , Clonación Molecular , Mutación
16.
J Bacteriol ; 181(20): 6469-77, 1999 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-10515939

RESUMEN

Aspergillus fumigatus, a filamentous fungus producing bluish-green conidia, is an important opportunistic pathogen that primarily affects immunocompromised patients. Conidial pigmentation of A. fumigatus significantly influences its virulence in a murine model. In the present study, six genes, forming a gene cluster spanning 19 kb, were identified as involved in conidial pigment biosynthesis in A. fumigatus. Northern blot analyses showed the six genes to be developmentally regulated and expressed during conidiation. The gene products of alb1 (for "albino 1"), arp1 (for "aspergillus reddish-pink 1"), and arp2 have high similarity to polyketide synthases, scytalone dehydratases, and hydroxynaphthalene reductases, respectively, found in the dihydroxynaphthalene (DHN)-melanin pathway of brown and black fungi. The abr1 gene (for "aspergillus brown 1") encodes a putative protein possessing two signatures of multicopper oxidases. The abr2 gene product has homology to the laccase encoded by the yA gene of Aspergillus nidulans. The function of ayg1 (for "aspergillus yellowish-green 1") remains unknown. Involvement of the six genes in conidial pigmentation was confirmed by the altered conidial color phenotypes that resulted from disruption of each gene in A. fumigatus. The presence of a DHN-melanin pathway in A. fumigatus was supported by the accumulation of scytalone and flaviolin in the arp1 deletant, whereas only flaviolin was accumulated in the arp2 deletants. Scytalone and flaviolin are well-known signature metabolites of the DHN-melanin pathway. Based on DNA sequence similarity, gene disruption results, and biochemical analyses, we conclude that the 19-kb DNA fragment contains a six-gene cluster which is required for conidial pigment biosynthesis in A. fumigatus. However, the presence of abr1, abr2, and ayg1 in addition to alb1, arp1, and arp2 suggests that conidial pigment biosynthesis in A. fumigatus is more complex than the known DHN-melanin pathway.


Asunto(s)
Aspergillus fumigatus/genética , Regulación Fúngica de la Expresión Génica , Genes Fúngicos , Melaninas/biosíntesis , Familia de Multigenes , Secuencia de Aminoácidos , Clonación Molecular , Dihidroxifenilalanina/análogos & derivados , Dihidroxifenilalanina/biosíntesis , Datos de Secuencia Molecular , Naftoles/metabolismo , Mapeo Restrictivo , Homología de Secuencia de Aminoácido , Esporas Fúngicas/genética
17.
Biochem Biophys Res Commun ; 216(1): 119-25, 1995 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-7488077

RESUMEN

The first pathway-specific step of ergot alkaloid biosynthesis in the fungus, Claviceps purpurea, is catalyzed by the prenyltransferase, 4-(gamma,gamma-dimethylallyl)tryptophan synthase. Partial sequence information was obtained for the purified enzyme and a degenerate oligonucleotide mixture was used to identify and amplify segments of the gene, dmaW. The complete gene and near-full-length cDNA were cloned and sequenced. The cDNA was cloned in a yeast expression vector in sense and antisense orientations relative to the inducible GAL1 promoter. Extracts of yeast transformants with the sense constructs, but not antisense constructs or cloning vector, catalyzed production of 4-(gamma,gamma-dimethylallyl)tryptophan. The sequence of dmaW and its cDNA indicated that it encoded a 455 amino acid polypeptide with a predicted molecular mass of 51,824 Da and a putative prenyl diphosphate binding motif.


Asunto(s)
Transferasas Alquil y Aril , Claviceps/enzimología , Claviceps/genética , Alcaloides de Claviceps/biosíntesis , Genes de Plantas , Transferasas/genética , Secuencia de Aminoácidos , Secuencia de Bases , Sistema Libre de Células , Claviceps/metabolismo , Clonación Molecular , Cartilla de ADN , Vectores Genéticos , Biblioteca Genómica , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae , Transferasas/biosíntesis , Transferasas/metabolismo
18.
Mol Microbiol ; 26(1): 175-83, 1997 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9383199

RESUMEN

Aspergillus fumigatus is an important pathogen causing invasive pulmonary aspergillosis in immunocompromised patients. The fungus propagates by conidia, which are the infectious structures inhaled by the human host. Opsonophagocytosis is thought to contribute to clearance of the inhaled conidia, a process that is facilitated by complement deposition on conidial surfaces. We now show that conidial colour mutants exhibit significant increases in C3 binding capacity compared with wild type. A reddish-pink mutation that led to enhanced C3 binding was complemented by a cosmid clone. A 3.3 kb DNA fragment from the subsequently rescued cosmid was sufficient to restore the bluish-green conidial pigment. The bluish-green transformant exhibited a level of C3 binding similar to that of the parental strain. A gene, designated arp1, was responsible for the complementation. Comparison of the genomic and cDNA sequences of arp1 revealed that it has two introns and encodes a putative protein of 168 amino acids. Arp1 is very similar to scytalone dehydratase, an enzyme involved in 1,8-dihydroxynaphthalene-melanin synthesis in Colletotrichum lagenarium and Magnaporthe grisea. Northern hybridization analysis revealed that arp1 is developmentally regulated, being expressed during conidiation. Disruption of arp1 resulted in reddish-pink conidia and increased C3 binding. Our studies suggest that arp1 modulates the bluish-green pigmentation of conidia as well as complement deposition.


Asunto(s)
Aspergillus fumigatus/genética , Complemento C3/metabolismo , Proteínas Fúngicas/genética , Hidroliasas/genética , Pigmentación/genética , Secuencia de Aminoácidos , Aspergillus fumigatus/inmunología , Aspergillus fumigatus/metabolismo , Northern Blotting , Southern Blotting , Clonación Molecular , Cósmidos/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/fisiología , Genes Fúngicos , Prueba de Complementación Genética , Hidroliasas/química , Hidroliasas/fisiología , Datos de Secuencia Molecular , Mutación , Fenotipo , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Transformación Genética/genética
19.
Hum Genet ; 100(2): 155-62, 1997 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9254842

RESUMEN

Machado-Joseph disease (MJD) is an autosomal dominant spinocerebellar degeneration characterized by cerebellar ataxia and pyramidal signs associated in varying degrees with a dystonic-rigid extrapyramidal syndrome or peripheral amyotrophy. Unstable CAG trinucleotide repeat expansion in the MJD gene on the long arm of chromosome 14 has been identified as the pathological mutation for MJD. While investigating the distribution of CAG repeat lengths of the MJD gene in Taiwan's population, we have identified 18 MJD-affected patients and 12 at-risk individuals in seven families. In addition, we have analyzed the range of CAG repeat lengths in 96 control individuals. The CAG repeat number ranged from 13 to 44 in the controls and 72-85 in the affected and at-risk individuals. Our results indicated that the CAG repeat number was inversely correlated with the age of onset. The differences in CAG repeat length between parent and child and between siblings are greater with paternal transmission than maternal transmission. Our data show a tendency towards the phenomenon of anticipation in the MJD families but do not support unidirectional expansion of CAG repeats during transmission. We also demonstrated that PCR amplification of the CAG repeats in the MJD gene from villous DNA was possible and might prove useful as a diagnostic tool for affected families in the future.


Asunto(s)
Pueblo Asiatico/genética , Enfermedad de Machado-Joseph/genética , Repeticiones de Trinucleótidos , Adulto , Edad de Inicio , Anciano , China/etnología , Vellosidades Coriónicas , Pruebas Genéticas , Humanos , Modelos Lineales , Enfermedad de Machado-Joseph/diagnóstico , Enfermedad de Machado-Joseph/epidemiología , Enfermedad de Machado-Joseph/etiología , Persona de Mediana Edad , Linaje , Diagnóstico Prenatal , Taiwán/epidemiología
20.
Appl Environ Microbiol ; 59(5): 1540-8, 1993 May.
Artículo en Inglés | MEDLINE | ID: mdl-8517749

RESUMEN

Many cool-season grasses (subfamily Pooideae) possess maternally transmitted fungal symbionts which cause no known pathology and often enhance the ecological fitness and biochemical capabilities of the grass hosts. The most commonly described endophytes are the Acremonium section Albo-lanosa spp. (Acremonium endophytes), which are conidial anamorphs (strictly asexual forms) of Epichloë typhina. Other endophytes which have been noted are a Gliocladium-like fungus in perennial ryegrass (Lolium perenne L.) and a Phialophora-like fungus in tall fescue (Festuca arundinacea Schreb.). Here, we report the identification of additional non-Acremonium sp. endophytes (herein designated p-endophytes) in three more grass species: Festuca gigantea, Festuca arizonica, and Festuca pratensis. In each grass species, the p-endophyte was cosymbiotic with an Acremonium endophyte. Serological analysis and sequence determinations of variable portions of their rRNA genes indicated that the two previously identified non-Acremonium endophytes are closely related to each other and to the newly identified p-endophytes. Therefore, the p-endophytes represent a second group of widely distributed grass symbionts.


Asunto(s)
Hongos Mitospóricos/fisiología , Poaceae/microbiología , Secuencia de Bases , ADN de Hongos/genética , Hongos Mitospóricos/clasificación , Hongos Mitospóricos/genética , Datos de Secuencia Molecular , Filogenia , Reacción en Cadena de la Polimerasa , Homología de Secuencia de Ácido Nucleico , Serotipificación , Simbiosis
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