Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
Photosynth Res ; 151(1): 125-142, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34669148

RESUMEN

The complete genome sequence of the thermophilic purple sulfur bacterium Thermochromatium tepidum strain MCT (DSM 3771T) is described and contrasted with that of its mesophilic relative Allochromatium vinosum strain D (DSM 180T) and other Chromatiaceae. The Tch. tepidum genome is a single circular chromosome of 2,958,290 base pairs with no plasmids and is substantially smaller than the genome of Alc. vinosum. The Tch. tepidum genome encodes two forms of RuBisCO and contains nifHDK and several other genes encoding a molybdenum nitrogenase but lacks a gene encoding a protein that assembles the Fe-S cluster required to form a functional nitrogenase molybdenum-iron cofactor, leaving the phototroph phenotypically Nif-. Tch. tepidum contains genes necessary for oxidizing sulfide to sulfate as photosynthetic electron donor but is genetically unequipped to either oxidize thiosulfate as an electron donor or carry out assimilative sulfate reduction, both of which are physiological hallmarks of Alc. vinosum. Also unlike Alc. vinosum, Tch. tepidum is obligately phototrophic and unable to grow chemotrophically in darkness by respiration. Several genes present in the Alc. vinosum genome that are absent from the genome of Tch. tepidum likely contribute to the major physiological differences observed between these related purple sulfur bacteria that inhabit distinct ecological niches.


Asunto(s)
Chromatiaceae , Chromatiaceae/genética , Análisis de Secuencia de ADN , Azufre
2.
Extremophiles ; 25(2): 159-172, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33590336

RESUMEN

Little is known about microbial ecosystems of interior Antarctica, if indeed such ecosystems exist. Although considerable research has assessed microorganisms indigenous to coastal regions of Antarctica, particularly their lakes, ponds, and soils, to our knowledge only one characterized bacterium, a strain of Pseudomonas, has been isolated from South Pole ice or snow. Metagenomic community analyses described in this work and elsewhere reveal that a diversity of bacteria exists in inland polar snows, yet attempts to culture and characterize these microbes from this extreme environment have been few to date. In this molecular and culture-dependent investigation of the microbiology of inland Antarctica, we enriched and isolated two new strains of bacteria and one strain of yeast (Fungi) from South Pole snow samples. The bacteria were of the genera Methylobacterium and Sphingomonas, and the yeast grouped with species of Naganishia (class Tremellocytes). In addition to phylogenetic analyses, characterization of these isolates included determinations of cell morphology, growth as a function of temperature, salinity tolerance, and carbon and energy source versatility. All organisms were found to be cold-adapted, and the yeast strain additionally showed considerable halotolerance. These descriptions expand our understanding of the diversity and metabolic activities of snowbound microorganisms of interior Antarctica.


Asunto(s)
Bacterias , Ecosistema , Regiones Antárticas , Bacterias/genética , Hongos , Filogenia
3.
Microorganisms ; 8(3)2020 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-32106460

RESUMEN

Despite significant interest and past work to elucidate the phylogeny and photochemistry of species of the Heliobacteriaceae, genomic analyses of heliobacteria to date have been limited to just one published genome, that of the thermophilic species Heliobacterium (Hbt.) modesticaldum str. Ice1T. Here we present an analysis of the complete genome of a second heliobacterium, Heliorestis (Hrs.) convoluta str. HHT, an alkaliphilic, mesophilic, and morphologically distinct heliobacterium isolated from an Egyptian soda lake. The genome of Hrs. convoluta is a single circular chromosome of 3.22 Mb with a GC content of 43.1% and 3263 protein-encoding genes. In addition to culture-based observations and insights gleaned from the Hbt. modesticaldum genome, an analysis of enzyme-encoding genes from key metabolic pathways supports an obligately photoheterotrophic lifestyle for Hrs. convoluta. A complete set of genes encoding enzymes for propionate and butyrate catabolism and the absence of a gene encoding lactate dehydrogenase distinguishes the carbon metabolism of Hrs. convoluta from its close relatives. Comparative analyses of key proteins in Hrs. convoluta, including cytochrome c553 and the Fo alpha subunit of ATP synthase, with those of related species reveal variations in specific amino acid residues that likely contribute to the success of Hrs. convoluta in its highly alkaline environment.

4.
Stroke Res Treat ; 2012: 385753, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23125943

RESUMEN

Background. Time from acute stroke to enrolment in clinical trials needs to be reduced to improve the chances of finding effective treatments. No completed randomised controlled trials of ambulance-based treatment for acute stroke have been reported in the UK, and the practicalities of recruiting, consenting, and treating patients are unknown. Methods. RIGHT is an ambulance based, single-blind, randomised controlled trial with blinded-outcome assessment. The trial will assess feasibility of using ambulance services to deliver ultra-acute stroke treatments; a secondary aim is to assess the effect of glyceryl trinitrate (GTN) on haemodynamic variables and functional outcomes. Initial consent, randomisation, and treatment are performed by paramedics prior to hospitalisation. Patients with ultra-acute stroke (≤4 hours of onset) are randomised to transdermal GTN (5 mg/24 hours) or gauze dressing daily for 7 days. The primary outcome is systolic blood pressure at 2 hours. Secondary outcomes include feasibility, haemodynamics, dependency, and other functional outcomes. A nested qualitative study is included. Trial Status. The trial has all relevant ethics and regulatory approvals and recruitment started on February 15, 2010. The trial stopped recruitment in December 2011 after 41 patients were recruited. Trial Registration. The trial registration number is ISRCTN66434824 and EudraCT number is 2007-004766-40.

5.
Arch Phys Med Rehabil ; 89(4): 652-9, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18373995

RESUMEN

OBJECTIVES: To use goal attainment scaling (GAS) to measure clinically important functional change in persons with multiple sclerosis (MS) and to assess its responsiveness compared with standard measures used to evaluate progress in rehabilitation. DESIGN: Prospective, observational cohort study. SETTING: Tertiary inpatient rehabilitation unit in Victoria, Australia. PARTICIPANTS: Consecutive sample of 24 persons with MS admitted for comprehensive rehabilitation program. The male-to-female ratio was 10:14, and the mean age +/- standard deviation was 52.0+/-8.3 years (range, 37-62y). Over half (n=14 [58.3%]) had secondary progressive MS. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: GAS scores were calculated for 5 to 10 priority goals set prospectively by each patient in agreement with the multidisciplinary treating team and compared with standard outcome measures-the FIM instrument and Barthel Index-rated on admission and discharge from the program. Patients were categorized into responders and nonresponders based on an overall clinical global impression. RESULTS: Of 203 selected goals, 167 were achieved at the predicted level. GAS recorded outcomes for 105 individualized goals not measured by the FIM and Barthel Index. Although all 3 measures showed statistically significant change from admission to discharge (P<.001), only GAS scores strongly correlated with the Clinical Global Impression scale (rho=-.86, P<.001). GAS discharge scores differed significantly between the responder and nonresponder groups (Mann-Whitney, z=-3.78, P<.001). Different measures of effect size gave different results, but GAS was consistently more responsive than either the FIM or Barthel Index. CONCLUSIONS: This preliminary study suggests that GAS is a responsive and useful outcome measure for the rehabilitation of persons with MS, providing added value to standardized outcome measurement.


Asunto(s)
Objetivos , Pacientes Internos , Esclerosis Múltiple/psicología , Esclerosis Múltiple/rehabilitación , Modalidades de Fisioterapia , Actividades Cotidianas , Adulto , Estudios de Cohortes , Femenino , Humanos , Tiempo de Internación , Masculino , Persona de Mediana Edad , Modelos Psicológicos , Esclerosis Múltiple/diagnóstico , Cooperación del Paciente , Alta del Paciente , Probabilidad , Estudios Prospectivos , Calidad de Vida , Centros de Rehabilitación , Medición de Riesgo , Índice de Severidad de la Enfermedad , Perfil de Impacto de Enfermedad , Análisis y Desempeño de Tareas , Victoria
6.
Pain ; 51(3): 267-272, 1992 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1491853

RESUMEN

This paper reports the development and validation of the Pain Beliefs Questionnaire (PBQ). This is a 20-item questionnaire covering beliefs about the cause and treatment of pain. It was administered to 294 subjects, comprising 100 chronic pain patients and 194 controls. An exploratory factor analysis revealed 2 factors accounting for 68.15% of the variance. From the final solution 2 scales were derived: the first called Organic Beliefs and the second Psychological Beliefs scale, comprising 8 and 4 items, respectively. The construct validity of the questionnaire was assessed in 2 ways. First, the responses of chronic pain patients and non-patient controls were compared: a significant difference (F(1,236) = 53.04, P < 0.0001) between these 2 groups emerged such that chronic pain patients were more likely to endorse the Organic Beliefs scale items, whereas non-patients were more likely to endorse the Psychological Beliefs scale items. Secondly, as predicted significant associations were observed between scores on the Organic Beliefs scale and scores on the Chance and Powerful Others scales of the Multidimensional Health Locus of Control (MHLC), and also between the Psychological Beliefs and Internal scales of the MHLC. No relationship, however, emerged between these scales and measures of pain intensity. The implications of these findings for the assessment and management of chronic pain patients, and in the understanding of the development of chronic pain, are discussed.


Asunto(s)
Dimensión del Dolor/instrumentación , Dolor/psicología , Análisis de Varianza , Artritis Reumatoide/complicaciones , Enfermedad Crónica , Femenino , Humanos , Control Interno-Externo , Masculino , Persona de Mediana Edad , Dolor/etiología , Encuestas y Cuestionarios
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...