RESUMEN
The inoculum size effect in the dimorphic fungus Candida albicans results from production of an extracellular quorum-sensing molecule (QSM). This molecule prevents mycelial development in both a growth morphology assay and a differentiation assay using three chemically distinct triggers for germ tube formation (GTF): L-proline, N-acetylglucosamine, and serum (either pig or fetal bovine). In all cases, the presence of QSM prevents the yeast-to-mycelium conversion, resulting in actively budding yeasts without influencing cellular growth rates. QSM exhibits general cross-reactivity within C. albicans in that supernatants from strain A72 are active on five other strains of C. albicans and vice versa. The QSM excreted by C. albicans is farnesol (C(15)H(26)O; molecular weight, 222.37). QSM is extracellular, and is produced continuously during growth and over a temperature range from 23 to 43 degrees C, in amounts roughly proportional to the CFU/milliliter. Production is not dependent on the type of carbon source nor nitrogen source or on the chemical nature of the growth medium. Both commercial mixed isomer and (E,E)-farnesol exhibited QSM activity (the ability to prevent GTF) at a level sufficient to account for all the QSM activity present in C. albicans supernatants, i.e., 50% GTF at ca. 30 to 35 microM. Nerolidol was ca. two times less active than farnesol. Neither geraniol (C(10)), geranylgeraniol (C(20)), nor farnesyl pyrophosphate had any QSM activity.
Asunto(s)
Candida albicans/crecimiento & desarrollo , Candida albicans/metabolismo , Farnesol/metabolismo , Farnesol/farmacología , Candida albicans/genética , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Medios de Cultivo , Farnesol/química , Farnesol/aislamiento & purificación , Cromatografía de Gases y Espectrometría de Masas , Regulación Fúngica de la Expresión Génica , CalorRESUMEN
This paper presents the genome organization and mobility of Pseudomonas aeruginosa strains that had been isolated in half-year intervals from 30 patients with cystic fibrosis since the onset of colonization over a 2- to 8-year period. The chromosomes were digested with DraI or SpeI, separated by pulsed-field gel electrophoresis, blotted and hybridized with probes encoding housekeeping or virulence genes. Strains were differentiated by relatedness of macrorestriction fingerprints. After some turnover of strains during the first two years of colonization, each patient had acquired a set of strains that diversified during the course of the disease. In the majority of patients, two clonal lineages were found to account for colonization in the air passages but each lung habitat was characterized by some specific signature of bands in the macrorestriction fragment pattern.
Asunto(s)
Electroforesis en Gel de Campo Pulsado/métodos , Pseudomonas aeruginosa/genética , Fibrosis Quística/complicaciones , Variación Genética , Humanos , Infecciones por Pseudomonas/complicaciones , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/aislamiento & purificación , Pseudomonas aeruginosa/patogenicidad , Factores de TiempoRESUMEN
To investigate the diagnostic value of video-EEG polysomnography (VPSG), we reviewed our experience in 122 patients with suspected parasomnias who underwent one or two nights of VPSG. Of 86 patients without known epilepsy, VPSG provided useful diagnostic information for 41 (69%) of those with a history of prominent motor activity during sleep and for 11 (41%) of those with a history of minor motor activity during sleep. Two children and one adult with clinical histories suggestive of sleep terrors had unequivocal partial seizures during VPSG. Of 36 patients with known epilepsy, VPSG was useful diagnostically in 28 (78%). VPSG is superior to standard polysomnography for the evaluation of parasomnias because of the increased capability to identify and localize EEG abnormalities and to correlate behavior with EEG and polysomnography. VPSG may also be a suitable alternative to intensive inpatient monitoring for some patients with known or suspected epilepsy who have frequent undiagnosed nocturnal spells.
Asunto(s)
Electroencefalografía , Trastornos del Sueño-Vigilia/diagnóstico , Sueño/fisiología , Grabación de Cinta de Video , Epilepsia/complicaciones , Estudios de Evaluación como Asunto , Femenino , Humanos , Persona de Mediana Edad , Actividad Motora , Trastornos del Sueño-Vigilia/etiología , Trastornos del Sueño-Vigilia/fisiopatologíaRESUMEN
Analyses made of seven dairy units revealed that clinically manifest udder inflammations had occurred once or repeatedly to 23.9 per cent of all cows in their first lactation and to 34.0 percent during the fourth lactation. Cows with no clinical udder inflammation in the first and second lactations were superior by 205 kg of milk to animals in whom such inflammations developed during the second lactation. Correlation coefficients between udder health and milk yield were between -0.22 and 0.32 and were likely to suggest that in the long run improvement of the genetic potential for milk yield was accompanied by deterioration of udder health. Therefore, udder health should be included by stabilising selection in Friesian dairy cattle breeding in the GDR. A sufficient breeding potential will be left for milk yield parameters, as was shown by simulated selection experiments.