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1.
Heart ; 95(15): 1238-44, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19457871

RESUMEN

BACKGROUND: Within the spectrum of congenital heart disease referred to as hypoplastic left heart syndrome (HLHS), there is variation in the morphology and function of the left ventricle which could influence outcomes after stage I Norwood palliation. OBJECTIVE: To determine if left ventricular (LV) morphology is associated with outcome after stage I Norwood palliation for HLHS. METHODS: Echocardiograms were reviewed from 108 patients who had undergone Norwood palliation at our institution over the past 11 years. Total cardiac diameter, thickness of the interventricular septum (IVS), LV area and LV myocardial area were calculated. Competing risk analysis was performed for survival to a stage II operation and to determine potential predictors. RESULTS: From the Norwood operation up to stage II operation, mortality was predicted by IVS thickness, while the absence of right ventricular (RV) dysfunction was predictive of survival to stage II operation. For the complete pathway, from Norwood to the Fontan operation, mortality was predicted by IVS, a lower RV fractional area change and the presence of significant tricuspid regurgitation. Cardiac transplantation during this period was predicted by a lower RV fractional area change (p = 0.02) and a larger LV area in diastole. CONCLUSIONS: These results indicate that LV hypertrophy and decreased RV function adversely effect survival after the Norwood operation. They suggest that LV morphology, especially septal hypertrophy, can influence outcomes in HLHS and should be considered when evaluating treatment options.


Asunto(s)
Síndrome del Corazón Izquierdo Hipoplásico/mortalidad , Síndrome del Corazón Izquierdo Hipoplásico/cirugía , Femenino , Trasplante de Corazón/mortalidad , Trasplante de Corazón/estadística & datos numéricos , Ventrículos Cardíacos/patología , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/patología , Lactante , Recién Nacido , Masculino , Calidad de Vida , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo , Análisis de Supervivencia
2.
Antimicrob Agents Chemother ; 50(12): 4202-5, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17015628

RESUMEN

The echinocandin caspofungin is a potent inhibitor of the activity of 1,3-beta-D-glucan synthase from Aspergillus flavus, Aspergillus terreus, and Aspergillus nidulans. In murine models of disseminated infection, caspofungin prolonged survival and reduced the kidney fungal burden. Caspofungin was at least as effective as amphotericin B against these filamentous fungi in vivo.


Asunto(s)
Antifúngicos/uso terapéutico , Aspergillus flavus/efectos de los fármacos , Aspergillus nidulans/efectos de los fármacos , Aspergillus/efectos de los fármacos , Péptidos Cíclicos/uso terapéutico , Animales , Caspofungina , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Equinocandinas , Femenino , Lipopéptidos , Ratones , Ratones Endogámicos DBA , Pruebas de Sensibilidad Microbiana , Análisis de Supervivencia , Factores de Tiempo , Resultado del Tratamiento
3.
Heredity (Edinb) ; 95(2): 129-35, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15815712

RESUMEN

The Viking age witnessed the expansion of Scandinavian invaders across much of northwestern Europe. While Scandinavian settlements had an enduring cultural impact on North Atlantic populations, the nature and extent of their genetic legacy in places such as Shetland and Orkney is not clear. In order to explore this question further, we have made an extensive survey of both Y-chromosomal and mitochondrial DNA (mtDNA) variation in the North Atlantic region. Our findings indicate an overall Scandinavian ancestry of approximately 44% for Shetland and approximately 30% for Orkney, with approximately equal contributions from Scandinavian male and female subjects in both cases. This contrasts with the situation for the Western Isles, where the overall Scandinavian ancestry is less ( approximately 15%) and where there is a disproportionately high contribution from Scandinavian males. In line with previous studies, we find that Iceland exhibits both the greatest overall amount of Scandinavian ancestry (55%) and the greatest discrepancy between Scandinavian male and female components. Our results suggest that while areas close to Scandinavia, such as Orkney and Shetland, may have been settled primarily by Scandinavian family groups, lone Scandinavian males, who later established families with female subjects from the British Isles, may have been prominent in areas more distant from their homeland.


Asunto(s)
ADN Mitocondrial , Emigración e Inmigración/historia , Linaje , Cromosomas Humanos Y/genética , Europa (Continente) , Femenino , Variación Genética , Herencia , Historia Medieval , Humanos , Masculino
4.
J Bacteriol ; 184(19): 5479-90, 2002 10.
Artículo en Inglés | MEDLINE | ID: mdl-12218036

RESUMEN

Virulence and immunity are poorly understood in Mycobacterium tuberculosis. We sequenced the complete genome of the M. tuberculosis clinical strain CDC1551 and performed a whole-genome comparison with the laboratory strain H37Rv in order to identify polymorphic sequences with potential relevance to disease pathogenesis, immunity, and evolution. We found large-sequence and single-nucleotide polymorphisms in numerous genes. Polymorphic loci included a phospholipase C, a membrane lipoprotein, members of an adenylate cyclase gene family, and members of the PE/PPE gene family, some of which have been implicated in virulence or the host immune response. Several gene families, including the PE/PPE gene family, also had significantly higher synonymous and nonsynonymous substitution frequencies compared to the genome as a whole. We tested a large sample of M. tuberculosis clinical isolates for a subset of the large-sequence and single-nucleotide polymorphisms and found widespread genetic variability at many of these loci. We performed phylogenetic and epidemiological analysis to investigate the evolutionary relationships among isolates and the origins of specific polymorphic loci. A number of these polymorphisms appear to have occurred multiple times as independent events, suggesting that these changes may be under selective pressure. Together, these results demonstrate that polymorphisms among M. tuberculosis strains are more extensive than initially anticipated, and genetic variation may have an important role in disease pathogenesis and immunity.


Asunto(s)
Evolución Molecular , Genoma Bacteriano , Mycobacterium tuberculosis/patogenicidad , Análisis de Secuencia de ADN , Tuberculosis/microbiología , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Variación Genética , Humanos , Datos de Secuencia Molecular , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/inmunología , Filogenia , Polimorfismo Genético , Polimorfismo de Nucleótido Simple , Alineación de Secuencia , Tuberculosis/inmunología
5.
Am J Hum Genet ; 69(4): 844-52, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11517423

RESUMEN

Mitochondrial HVS-I sequences from 10,365 subjects belonging to 56 populations/geographical regions of western Eurasia and northern Africa were first surveyed for the presence of the T-->C transition at nucleotide position 16298, a mutation which has previously been shown to characterize haplogroup V mtDNAs. All mtDNAs with this mutation were then screened for a number of diagnostic RFLP sites, revealing two major subsets of mtDNAs. One is haplogroup V proper, and the other has been termed "pre*V," since it predates V phylogenetically. The rather uncommon pre*V tends to be scattered throughout Europe (and northwestern Africa), whereas V attains two peaks of frequency: one situated in southwestern Europe and one in the Saami of northern Scandinavia. Geographical distributions and ages support the scenario that pre*V originated in Europe before the Last Glacial Maximum (LGM), whereas the more recently derived haplogroup V arose in a southwestern European refugium soon after the LGM. The arrival of V in eastern/central Europe, however, occurred much later, possibly with (post-)Neolithic contacts. The distribution of haplogroup V mtDNAs in modern European populations would thus, at least in part, reflect the pattern of postglacial human recolonization from that refugium, affecting even the Saami. Overall, the present study shows that the dissection of mtDNA variation into small and well-defined evolutionary units is an essential step in the identification of spatial frequency patterns. Mass screening of a few markers identified using complete mtDNA sequences promises to be an efficient strategy for inferring features of human prehistory.


Asunto(s)
Clima Frío , ADN Mitocondrial/genética , Emigración e Inmigración , Frecuencia de los Genes/genética , Hielo , Filogenia , África del Norte , Asia Occidental , Europa (Continente) , Marcadores Genéticos/genética , Pruebas Genéticas , Haplotipos/genética , Humanos , Mutación/genética , Polimorfismo de Longitud del Fragmento de Restricción , Tamaño de la Muestra , Factores de Tiempo
6.
Science ; 293(5529): 498-506, 2001 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-11463916

RESUMEN

The 2,160,837-base pair genome sequence of an isolate of Streptococcus pneumoniae, a Gram-positive pathogen that causes pneumonia, bacteremia, meningitis, and otitis media, contains 2236 predicted coding regions; of these, 1440 (64%) were assigned a biological role. Approximately 5% of the genome is composed of insertion sequences that may contribute to genome rearrangements through uptake of foreign DNA. Extracellular enzyme systems for the metabolism of polysaccharides and hexosamines provide a substantial source of carbon and nitrogen for S. pneumoniae and also damage host tissues and facilitate colonization. A motif identified within the signal peptide of proteins is potentially involved in targeting these proteins to the cell surface of low-guanine/cytosine (GC) Gram-positive species. Several surface-exposed proteins that may serve as potential vaccine candidates were identified. Comparative genome hybridization with DNA arrays revealed strain differences in S. pneumoniae that could contribute to differences in virulence and antigenicity.


Asunto(s)
Genoma Bacteriano , Análisis de Secuencia de ADN , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/patogenicidad , Antígenos Bacterianos , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/inmunología , Proteínas Bacterianas/metabolismo , Vacunas Bacterianas , Composición de Base , Metabolismo de los Hidratos de Carbono , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Cromosomas Bacterianos/genética , Biología Computacional , Elementos Transponibles de ADN , ADN Bacteriano/química , ADN Bacteriano/genética , Duplicación de Gen , Genes Bacterianos , Hexosaminas/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , Recombinación Genética , Secuencias Repetitivas de Ácidos Nucleicos , Especificidad de la Especie , Streptococcus pneumoniae/inmunología , Streptococcus pneumoniae/metabolismo , Virulencia , Operón de ARNr
7.
Free Radic Biol Med ; 31(2): 139-52, 2001 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-11440826

RESUMEN

Diclofenac (DCLF) is a nonsteroidal anti-inflammatory drug that is widely used for the treatment of osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, and acute muscle pain conditions. Toxic doses of DCLF can cause nephrotoxicity in humans and experimental animals. However, whether this DCLF-induced nephrotoxicity involves apoptotic cell death in addition to necrosis is unknown. The goals of this investigation were to determine whether DCLF-induced nephrotoxicity involves oxidative stress and apoptotic type genomic DNA fragmentation, and if so, whether DCLF-induced oxidative stress and DNA fragmentation cause apoptotic cell death in mouse kidneys. Male ICR mice (CD-1; 25-45 g), fed ad libitum, were administered nephrotoxic doses of DCLF (100, 200, 300 mg/Kg, po) and sacrificed 24 h later. Blood was collected to evaluate renal injury (BUN), lipid peroxidation (MDA: malondialdehyde levels), and superoxide dismutase (SOD) activity (a marker of oxidative stress). Kidney tissues were analyzed both quantitatively and qualitatively to determine the degree and type of DNA damage, and evaluated histopathologically for the presence of apoptotic characteristics in the nucleus of diverse types of kidney cells. Results show that diclofenac is a powerful nephrotoxicant (at 100, 200, and 300 mg/kg: 4.7-, 4.9-, and 5.0-fold increases in BUN compared to the control, respectively) and a strong inducer of oxidative stress (significant increase in MDA levels). Oxidative stress induced by DCLF was also coupled with massive kidney DNA fragmentation (100, 200, and 300 mg/kg: 3-, 8-, and 10-fold increases compared to control, respectively). A dose-dependent increase in MDA levels and SOD activity was also observed, which indicated a link between oxidative stress and nephrotoxicity. Qualitative analysis of DNA fragmentation by gel electrophoresis showed a DNA ladder indicative of Ca2+-Mg2+-endonuclease activation. Histopathological examination of kidney sections revealed numerous apoptotic nuclei across proximal and distal tubular cell linings. Collectively, these data for the first time suggest that DCLF-induced nephrotoxicity may involve production of reactive oxygen species leading to oxidative stress and massive genomic DNA fragmentation, and these two free radical mediated events may ultimately translate into apoptotic cell death of kidney cells in vivo, and reveal a DNA-active role for DCLF.


Asunto(s)
Antiinflamatorios no Esteroideos/toxicidad , Diclofenaco/toxicidad , Riñón/efectos de los fármacos , Animales , Apoptosis/efectos de los fármacos , Fragmentación del ADN/efectos de los fármacos , Endodesoxirribonucleasas/metabolismo , Activación Enzimática/efectos de los fármacos , Humanos , Riñón/metabolismo , Riñón/patología , Peroxidación de Lípido/efectos de los fármacos , Masculino , Malondialdehído/sangre , Ratones , Ratones Endogámicos ICR , Necrosis , Estrés Oxidativo/efectos de los fármacos , Superóxido Dismutasa/sangre
8.
J Med Chem ; 44(15): 2421-31, 2001 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-11448224

RESUMEN

p56lck is a member of the src family of tyrosine kinases and plays a critical role in the signal transduction events that lead to T cell activation. Ligands for the p56lck SH2 domain have the potential to disrupt the interaction of p56lck with its substrates and derail the signaling cascade that leads to the production of cytokines such as interleukin-2. Starting from the quintuply charged (at physiological pH) phosphorylated tetrapeptide, AcpYEEI, we recently disclosed (J. Med. Chem. 1999, 42, 722 and J. Med. Chem. 1999, 42, 1757) the design of the modified dipeptide 3, which carries just two charges at physiological pH. Here we present the elaboration of 3 to the nonpeptidic, monocharged compound, 9S. This molecule displays good binding affinity for the p56lck SH2 domain (K(d) 1 microM) and good cell permeation, and this combination of properties allowed us to demonstrate clear-cut inhibitory effects on a very early event in T cell activation, namely calcium mobilization.


Asunto(s)
Permeabilidad de la Membrana Celular , Proteína Tirosina Quinasa p56(lck) Específica de Linfocito/metabolismo , Fenilalanina/síntesis química , Piridonas/síntesis química , Dominios Homologos src , Células CACO-2 , Calcio/metabolismo , Humanos , Células Jurkat , Ligandos , Modelos Moleculares , Fenilalanina/análogos & derivados , Fenilalanina/química , Fenilalanina/farmacología , Piridonas/química , Piridonas/farmacología
9.
Mol Cell Biochem ; 218(1-2): 27-33, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11330834

RESUMEN

Previous studies from our laboratories have linked the protective abilities of IH636 grape seed proanthocyanidin extract (GSPE) with inactivation of anti-apoptotic gene bcl-XL, and modification of several other critical molecular targets such as DNA-damage/DNA-repair, lipid peroxidation and intracellular Ca2+ homeostasis. Especially, GSPE provided dramatic protection against acetaminophen (APAP)-induced hepatotoxicity, significantly increased bcl-XL expression in the liver, and antagonized both necrotic and apoptotic deaths of liver cells in vivo. However, it was not clear from this study whether anti-apoptogenic and anti-necrotic effects of GSPE were: (i) due to its interference with endonuclease activity, (ii) due to its antioxidant effect, or, (iii) due to its ability to inhibit microsomal drug metabolizing enzyme(s), such as CYP-4502E1. Since CYP-4502E1 primarily metabolizes acetaminophen in mice and rats, this study specifically focused on CYP-4502E1's catalytic activity in vitro. Overall this investigation compared the in vitro aniline hydroxylation patterns of: (i) in vivo GSPE-exposed and unexposed (control) mouse liver microsomes, (ii) induced (1% acetone in drinking water for 3 days) and uninduced rat liver microsomes in the presence and absence of GSPE in vitro, and (iii) control rat liver microsomes in the presence of an anti-APAP agent 4-aminobenzamide (4-AB) in vitro. For the in vivo assessment, male B6C3F1 mice were fed GSPE diet (ADI 100 mg/kg body wt) for 4 weeks, and liver microsomes were isolated from both control and GSPE-fed mice for aniline hydroxylation, a specific marker of CYP-4502E1 activity. Data show that hydroxylation was 40% less in microsomes from GSPE-exposed livers compared to control microsomes. Similarly, when rat liver microsomes were incubated with various concentrations of GSPE in vitro (100 and 250 microg/ml), aniline hydroxylation was inhibited to various degrees (uninduced: 40 and 60% and induced: 25 and 50%, respectively with 100 and 250 microg/ml). Influence of GSPE on hydroxylation patterns were compared with another hepatoprotective agent 4-aminobenzamide (4-AB), a well-known modulator of nuclear enzyme poly(ADP-ribose) polymerase, and the data shows that 4-AB did not alter aniline hydroxylation at all. Collectively, these results may suggest that GSPE has the ability to inhibit CYP-4502E1, and this is an additional cytoprotective attribute, in conjunction with its novel antioxidant and/or antiendonucleolytic potential.


Asunto(s)
Ácido 4-Aminobenzoico/farmacología , Acetaminofén/farmacología , Compuestos de Anilina/metabolismo , Sistema Enzimático del Citocromo P-450/metabolismo , Citoprotección/efectos de los fármacos , Microsomas Hepáticos/efectos de los fármacos , Extractos Vegetales/farmacología , para-Aminobenzoatos , Acetona/administración & dosificación , Acetona/farmacología , Administración Oral , Animales , Benzamidas , Disponibilidad Biológica , Catálisis/efectos de los fármacos , Reparación del ADN , Relación Dosis-Respuesta a Droga , Extracto de Semillas de Uva , Técnicas In Vitro , Isoenzimas/metabolismo , Masculino , Ratones , Ratones Endogámicos , Extractos Vegetales/administración & dosificación , Proantocianidinas , Ratas , Ratas Sprague-Dawley
10.
Am J Hum Genet ; 68(3): 723-37, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11179019

RESUMEN

A total of 1,664 new mtDNA control-region sequences were analyzed in order to estimate Gaelic and Scandinavian matrilineal ancestry in the populations of Iceland, Orkney, the Western Isles, and the Isle of Skye and to investigate other aspects of their genetic history. A relative excess of private lineages in the Icelanders is indicative of isolation, whereas the scarcity of private lineages in Scottish island populations may be explained by recent gene flow and population decline. Differences in the frequencies of lineage clusters are observed between the Scandinavian and the Gaelic source mtDNA pools, and, on a continent-wide basis, such differences between populations seem to be associated with geography. A multidimensional scaling analysis of genetic distances, based on mtDNA lineage-cluster frequencies, groups the North Atlantic islanders with the Gaelic and the Scandinavian populations, whereas populations from the central, southern, and Baltic regions of Europe are arranged in clusters in broad agreement with their geographic locations. This pattern is highly significant, according to a Mantel correlation between genetic and geographic distances (r=.716). Admixture analyses indicate that the ancestral contributions of mtDNA lineages from Scandinavia to the populations of Iceland, Orkney, the Western Isles, and the Isle of Skye are 37.5%, 35.5%, 11.5%, and 12.5%, respectively.


Asunto(s)
ADN Mitocondrial/genética , Etnicidad/genética , Filogenia , Islas del Atlántico , Femenino , Impresión Genómica , Haplotipos , Humanos , Masculino , Datos de Secuencia Molecular , Países Escandinavos y Nórdicos/etnología , Escocia/etnología
11.
Nucleic Acids Res ; 29(1): 123-5, 2001 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-11125067

RESUMEN

One challenge presented by large-scale genome sequencing efforts is effective display of uniform information to the scientific community. The Comprehensive Microbial Resource (CMR) contains robust annotation of all complete microbial genomes and allows for a wide variety of data retrievals. The bacterial information has been placed on the Web at http://www.tigr.org/CMR for retrieval using standard web browsing technology. Retrievals can be based on protein properties such as molecular weight or hydrophobicity, GC-content, functional role assignments and taxonomy. The CMR also has special web-based tools to allow data mining using pre-run homology searches, whole genome dot-plots, batch downloading and traversal across genomes using a variety of datatypes.


Asunto(s)
Bacterias/genética , Bases de Datos Factuales , Genes Bacterianos/genética , Genoma Bacteriano , Servicios de Información , Internet
12.
Am J Med Qual ; 16(6): 189-95, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11816849

RESUMEN

Clinical practice guidelines are an important tool for improving quality of care. This study determined whether and how guidelines are being used in nursing homes. We surveyed staff at 36 Department of Veterans Affairs (VA) nursing homes. Employees were asked whether they were familiar with guidelines as well as whether 5 specific guidelines had been read, were available, and had been adopted. Among 1065 respondents (60% of those surveyed), 79% reported familiarity with guidelines. The proportion of staff at a facility reporting adoption was generally less than 50%. Those nursing homes in which a high percentage of the staff reported adoption of one guideline were more likely to have adopted other guidelines. However, staff were not more likely to report adoption of a specific guideline when the nurse manager stated that it was adopted. We conclude that staff at VA nursing homes are familiar with guidelines. Guideline adoption at individual nursing homes, however, is not a systematic process involving the entire staff.


Asunto(s)
Casas de Salud/normas , Guías de Práctica Clínica como Asunto , Garantía de la Calidad de Atención de Salud/métodos , Difusión de Innovaciones , Adhesión a Directriz/estadística & datos numéricos , Encuestas de Atención de la Salud , Personal de Salud/educación , Humanos , Neoplasias/complicaciones , Dolor/etiología , Manejo del Dolor , Cuidados Paliativos , Úlcera por Presión/prevención & control , Úlcera por Presión/terapia , Rehabilitación de Accidente Cerebrovascular , Estados Unidos , United States Department of Veterans Affairs , Incontinencia Urinaria/terapia
13.
Am J Hum Genet ; 67(5): 1251-76, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11032788

RESUMEN

Founder analysis is a method for analysis of nonrecombining DNA sequence data, with the aim of identification and dating of migrations into new territory. The method picks out founder sequence types in potential source populations and dates lineage clusters deriving from them in the settlement zone of interest. Here, using mtDNA, we apply the approach to the colonization of Europe, to estimate the proportion of modern lineages whose ancestors arrived during each major phase of settlement. To estimate the Palaeolithic and Neolithic contributions to European mtDNA diversity more accurately than was previously achievable, we have now extended the Near Eastern, European, and northern-Caucasus databases to 1,234, 2, 804, and 208 samples, respectively. Both back-migration into the source population and recurrent mutation in the source and derived populations represent major obstacles to this approach. We have developed phylogenetic criteria to take account of both these factors, and we suggest a way to account for multiple dispersals of common sequence types. We conclude that (i) there has been substantial back-migration into the Near East, (ii) the majority of extant mtDNA lineages entered Europe in several waves during the Upper Palaeolithic, (iii) there was a founder effect or bottleneck associated with the Last Glacial Maximum, 20,000 years ago, from which derives the largest fraction of surviving lineages, and (iv) the immigrant Neolithic component is likely to comprise less than one-quarter of the mtDNA pool of modern Europeans.


Asunto(s)
ADN Mitocondrial/genética , Efecto Fundador , Pool de Genes , Filogenia , Bases de Datos como Asunto , Emigración e Inmigración , Europa (Continente) , Herencia Extracromosómica/genética , Frecuencia de los Genes/genética , Variación Genética/genética , Haplotipos/genética , Humanos , Medio Oriente/etnología , Mutagénesis , Factores de Tiempo
14.
Nature ; 406(6795): 477-83, 2000 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-10952301

RESUMEN

Here we determine the complete genomic sequence of the gram negative, gamma-Proteobacterium Vibrio cholerae El Tor N16961 to be 4,033,460 base pairs (bp). The genome consists of two circular chromosomes of 2,961,146 bp and 1,072,314 bp that together encode 3,885 open reading frames. The vast majority of recognizable genes for essential cell functions (such as DNA replication, transcription, translation and cell-wall biosynthesis) and pathogenicity (for example, toxins, surface antigens and adhesins) are located on the large chromosome. In contrast, the small chromosome contains a larger fraction (59%) of hypothetical genes compared with the large chromosome (42%), and also contains many more genes that appear to have origins other than the gamma-Proteobacteria. The small chromosome also carries a gene capture system (the integron island) and host 'addiction' genes that are typically found on plasmids; thus, the small chromosome may have originally been a megaplasmid that was captured by an ancestral Vibrio species. The V. cholerae genomic sequence provides a starting point for understanding how a free-living, environmental organism emerged to become a significant human bacterial pathogen.


Asunto(s)
Cromosomas Bacterianos , ADN Bacteriano , Vibrio cholerae/genética , Secuencia de Bases , Transporte Biológico , Cólera/microbiología , Reparación del ADN , Metabolismo Energético , Evolución Molecular , Regulación Bacteriana de la Expresión Génica , Genoma Bacteriano , Humanos , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADN , Vibrio cholerae/clasificación , Vibrio cholerae/patogenicidad
15.
Science ; 287(5459): 1809-15, 2000 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-10710307

RESUMEN

The 2,272,351-base pair genome of Neisseria meningitidis strain MC58 (serogroup B), a causative agent of meningitis and septicemia, contains 2158 predicted coding regions, 1158 (53.7%) of which were assigned a biological role. Three major islands of horizontal DNA transfer were identified; two of these contain genes encoding proteins involved in pathogenicity, and the third island contains coding sequences only for hypothetical proteins. Insights into the commensal and virulence behavior of N. meningitidis can be gleaned from the genome, in which sequences for structural proteins of the pilus are clustered and several coding regions unique to serogroup B capsular polysaccharide synthesis can be identified. Finally, N. meningitidis contains more genes that undergo phase variation than any pathogen studied to date, a mechanism that controls their expression and contributes to the evasion of the host immune system.


Asunto(s)
Genoma Bacteriano , Neisseria meningitidis/genética , Neisseria meningitidis/patogenicidad , Análisis de Secuencia de ADN , Variación Antigénica , Antígenos Bacterianos/inmunología , Bacteriemia/microbiología , Cápsulas Bacterianas/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/fisiología , Elementos Transponibles de ADN , Evolución Molecular , Fimbrias Bacterianas/genética , Humanos , Meningitis Meningocócica/microbiología , Infecciones Meningocócicas/microbiología , Datos de Secuencia Molecular , Mutación , Neisseria meningitidis/clasificación , Neisseria meningitidis/fisiología , Sistemas de Lectura Abierta , Operón , Filogenia , Recombinación Genética , Serotipificación , Transformación Bacteriana , Virulencia/genética
16.
Mol Microbiol ; 35(3): 490-516, 2000 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10672174

RESUMEN

We have determined that Borrelia burgdorferi strain B31 MI carries 21 extrachromosomal DNA elements, the largest number known for any bacterium. Among these are 12 linear and nine circular plasmids, whose sequences total 610 694 bp. We report here the nucleotide sequence of three linear and seven circular plasmids (comprising 290 546 bp) in this infectious isolate. This completes the genome sequencing project for this organism; its genome size is 1 521 419 bp (plus about 2000 bp of undetermined telomeric sequences). Analysis of the sequence implies that there has been extensive and sometimes rather recent DNA rearrangement among a number of the linear plasmids. Many of these events appear to have been mediated by recombinational processes that formed duplications. These many regions of similarity are reflected in the fact that most plasmid genes are members of one of the genome's 161 paralogous gene families; 107 of these gene families, which vary in size from two to 41 members, contain at least one plasmid gene. These rearrangements appear to have contributed to a surprisingly large number of apparently non-functional pseudogenes, a very unusual feature for a prokaryotic genome. The presence of these damaged genes suggests that some of the plasmids may be in a period of rapid evolution. The sequence predicts 535 plasmid genes >/=300 bp in length that may be intact and 167 apparently mutationally damaged and/or unexpressed genes (pseudogenes). The large majority, over 90%, of genes on these plasmids have no convincing similarity to genes outside Borrelia, suggesting that they perform specialized functions.


Asunto(s)
Grupo Borrelia Burgdorferi/genética , Borrelia burgdorferi , ADN Circular , Genoma Bacteriano , Enfermedad de Lyme/microbiología , Secuencia de Bases , División Celular/genética , Cromosomas Bacterianos , Replicación del ADN , Evolución Molecular , Técnicas de Transferencia de Gen , Lipoproteínas/genética , Datos de Secuencia Molecular , Plásmidos/genética , Seudogenes , Recombinación Genética , Análisis de Secuencia de ADN , Secuencias Repetidas en Tándem , Telómero
17.
Nucleic Acids Res ; 28(6): 1397-406, 2000 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-10684935

RESUMEN

The genome sequences of Chlamydia trachomatis mouse pneumonitis (MoPn) strain Nigg (1 069 412 nt) and Chlamydia pneumoniae strain AR39 (1 229 853 nt) were determined using a random shotgun strategy. The MoPn genome exhibited a general conservation of gene order and content with the previously sequenced C.trachomatis serovar D. Differences between C.trachomatis strains were focused on an approximately 50 kb 'plasticity zone' near the termination origins. In this region MoPn contained three copies of a novel gene encoding a >3000 amino acid toxin homologous to a predicted toxin from Escherichia coli O157:H7 but had apparently lost the tryptophan biosyntheis genes found in serovar D in this region. The C. pneumoniae AR39 chromosome was >99.9% identical to the previously sequenced C.pneumoniae CWL029 genome, however, comparative analysis identified an invertible DNA segment upstream of the uridine kinase gene which was in different orientations in the two genomes. AR39 also contained a novel 4524 nt circular single-stranded (ss)DNA bacteriophage, the first time a virus has been reported infecting C. pneumoniae. Although the chlamydial genomes were highly conserved, there were intriguing differences in key nucleotide salvage pathways: C.pneumoniae has a uridine kinase gene for dUTP production, MoPn has a uracil phosphororibosyl transferase, while C.trachomatis serovar D contains neither gene. Chromosomal comparison revealed that there had been multiple large inversion events since the species divergence of C.trachomatis and C.pneumoniae, apparently oriented around the axis of the origin of replication and the termination region. The striking synteny of the Chlamydia genomes and prevalence of tandemly duplicated genes are evidence of minimal chromosome rearrangement and foreign gene uptake, presumably owing to the ecological isolation of the obligate intracellular parasites. In the absence of genetic analysis, comparative genomics will continue to provide insight into the virulence mechanisms of these important human pathogens.


Asunto(s)
Chlamydia trachomatis/genética , Chlamydophila pneumoniae/genética , Genoma Bacteriano , Animales , Proteínas Bacterianas/genética , Bacteriófagos/genética , Secuencia de Bases , Infecciones por Chlamydia/microbiología , Chlamydia trachomatis/enzimología , Chlamydia trachomatis/metabolismo , Chlamydia trachomatis/patogenicidad , Chlamydophila pneumoniae/enzimología , Chlamydophila pneumoniae/patogenicidad , Chlamydophila pneumoniae/virología , Inversión Cromosómica , Secuencia Conservada/genética , Evolución Molecular , Genes Bacterianos/genética , Genes Duplicados/genética , Humanos , Ratones/microbiología , Datos de Secuencia Molecular , Nucleótidos/metabolismo , Mapeo Físico de Cromosoma , Recombinación Genética/genética , Origen de Réplica/genética
18.
J Org Chem ; 65(26): 9160-71, 2000 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-11149865

RESUMEN

The cis,trans trispiro ether 4 is accessible from several synthetic directions as a consequence of a crossover in reaction selectivity when proceeding from nucleophilic attack on the cis dispiro ketone to oxygenation of the alpha,beta-unsaturated ester 17. Its cis,cis isomer 3 was obtained in 17 steps and 14.6% overall yield from 3, 5-dimethoxybenzoic acid by making use of the alicyclic side chain in N as a "conformational lock". Although 4 shows no measurable tendency to complex with alkali metal ions, 3 binds strongly to Li(+) and Na(+) ions, as well as to CH(3)NH(3)(+). Whereas the 3eq conformation is populated in the solid state and in solution, complex formation occurs readily. (13)C NMR studies have defined slow exchange limits as the 2:1 sandwich complex with lithium ion is initially formed and transformed progressively into a 1:1 species upon the addition of more LiClO(4). Only the 2:1 complex with sodium ion is formed during comparable titration with NaClO(4). Association constants, molecular mechanics calculations, and X-ray crystallographic studies provide insight into the binding capacity of this belted tridentate ionophore.


Asunto(s)
Furanos/química , Ionóforos/síntesis química , Compuestos de Espiro/síntesis química , Cristalografía por Rayos X , Ionóforos/química , Ligandos , Metales Alcalinos/química , Modelos Moleculares , Conformación Molecular , Espectrometría de Masa Bombardeada por Átomos Veloces , Compuestos de Espiro/química , Estereoisomerismo
19.
Science ; 286(5444): 1571-7, 1999 Nov 19.
Artículo en Inglés | MEDLINE | ID: mdl-10567266

RESUMEN

The complete genome sequence of the radiation-resistant bacterium Deinococcus radiodurans R1 is composed of two chromosomes (2,648,638 and 412,348 base pairs), a megaplasmid (177,466 base pairs), and a small plasmid (45,704 base pairs), yielding a total genome of 3,284, 156 base pairs. Multiple components distributed on the chromosomes and megaplasmid that contribute to the ability of D. radiodurans to survive under conditions of starvation, oxidative stress, and high amounts of DNA damage were identified. Deinococcus radiodurans represents an organism in which all systems for DNA repair, DNA damage export, desiccation and starvation recovery, and genetic redundancy are present in one cell.


Asunto(s)
Genoma Bacteriano , Cocos Grampositivos/genética , Mapeo Físico de Cromosoma , Análisis de Secuencia de ADN , Proteínas Bacterianas/biosíntesis , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Catalasa/genética , Cromosomas Bacterianos/genética , Daño del ADN , Reparación del ADN/genética , ADN Bacteriano/genética , Metabolismo Energético , Genes Bacterianos , Cocos Grampositivos/química , Cocos Grampositivos/clasificación , Cocos Grampositivos/efectos de la radiación , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Estrés Oxidativo , Plásmidos , Tolerancia a Radiación , Secuencias Repetitivas de Ácidos Nucleicos , Superóxido Dismutasa/genética , Thermus/química , Thermus/genética , Rayos Ultravioleta
20.
Gene Expr ; 7(4-6): 349-55, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10440235

RESUMEN

Recent reports have demonstrated that the heat shock proteins (hsp) and in particular the hsp70 confer protection against cardiac ischemic damage. More recently, we have shown that increased expression of another heat shock protein, the hsp27, through an adenovirus vector system protects adult cardiomyocytes against ischemic injury. This small heat shock protein undergoes phosphorylation when the cell is under stress. This has led many to speculate that phosphorylation of hsp27 is required for the protective role this protein plays in the cell. In order to investigate this possibility, we have mutated the serines that are the sites of phosphorylation on the hsp27, to glycines or alanines. These nonphosphorylatable mutants of hsp27 were cloned into adenoviral vectors and used to infect adult rat cardiomyocytes to assess their ability in protecting against ischemic injury. In addition, we used a specific inhibitor of p38 MAP kinase that is a key member of the kinase pathway responsible for phosphorylating the hsp27. Our present results show that the nonphosphorylated hsp27 forms larger oligomeric complexes than the phosphorylated hsp27. Interestingly, phosphorylation of hsp27 seems not to play a role in its ability to protect adult rat cardiomyocytes against ischemic damage.


Asunto(s)
Proteínas de Choque Térmico/fisiología , Proteínas Quinasas Activadas por Mitógenos , Isquemia Miocárdica/prevención & control , Miocardio/metabolismo , Animales , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Células Cultivadas , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Miocardio/citología , Fosforilación , Ratas , Ratas Sprague-Dawley , Proteínas Quinasas p38 Activadas por Mitógenos
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