Development and use of a quantum dot probe to track multiple yeast strains in mixed culture

Published 10 November 2014Saccharomyces cerevisiae strains vary in their ability to develop and enhance sensory attributes of alcoholic beverages and are often found growing in mixed strain fermentations; however, quantifying individual strains is challenging due to quantification inaccuracies, low marker longevity, and compromised kinetics. We developed a fluorescent probe, consisting of glutathione molecules conjugated to a quantum dot (QD). Two S. cerevisiae strains were incubated with different coloured probes (QD attached to glutathione molecules, QD-GSH), fermented at multiple ratios, and quantified using confocal microscopy. The QD method was compared with a culture method using microsatellite DNA analysis (MS method). Probes were taken up by an ADP1 encoded transporter, transferred from mother cell to daughter cell, detectable in strains throughout fermentation, and were non-toxic. This resulted in a new quantification method that was more accurate and efficient than the MS method.Frida S. Gustafsson, Matthew D. Whiteside, Vladimir Jiranek and Daniel M. Dural

Ostectomía en Cuña de la Tibia como Tratamiento de la Rotura del Ligamento Cruzado Anterior. Estudio Retrospectivo

Analizar los resultados retrospectivos de 52 ostectomías en cuña de la tibia como tratamiento de la rotura del ligamento cruzado anterior. Específicos: • Caracterizar la población con rotura de ligamento cruzado anterior. • Describir los tipos de rotura y lesiones asociadas. • Calcular el ángulo de inclinación de la meseta tibial pre y post quirúrgico. • Analizar la evolución y resultados de la técnica de la ostectomía tibial en cuña

Plant-Mycorrhiza Percent Infection as Evidence of Coupled Metabolism

A common feature of mycorrhizal observation is the growth of the infection on the plant root as a percent of the infected root or root tip length. Often, this is measured as a logistic curve with an eventual, though usually transient, plateau. It is shown in this paper that the periods of stable percent infection in the mycorrhizal growth cycle correspond to periods where both the plant and mycorrhiza growth rates and likely metabolism are tightly coupled.Comment: 11 pages; accepted by the Journal of Theoretical Biology (in press

Withdrawal of life-support in paediatric intensive care - a study of time intervals between discussion, decision and death

<p>Abstract</p> <p>Background</p> <p>Scant information exists about the time-course of events during withdrawal of life-sustaining treatment. We investigated the time required for end-of-life decisions, subsequent withdrawal of life-sustaining treatment and the time to death.</p> <p>Methods</p> <p>Prospective, observational study in the ICU of a tertiary paediatric hospital.</p> <p>Results</p> <p>Data on 38 cases of withdrawal of life-sustaining treatment were recorded over a 12-month period (75% of PICU deaths). The time from the first discussion between medical staff and parents of the subject of withdrawal of life-sustaining treatment to parents and medical staff making the decision varied widely from immediate to 457 hours (19 days) with a median time of 67.8 hours (2.8 days). Large variations were subsequently also observed from the time of decision to actual commencement of the process ranging from 30 minutes to 47.3 hrs (2 days) with a median requirement of 4.7 hours. Death was apparent to staff at a median time of 10 minutes following withdrawal of life support varying from immediate to a maximum of 6.4 hours. Twenty-one per cent of children died more than 1 hour after withdrawal of treatment. Medical confirmation of death occurred at 0 to 35 minutes thereafter with the physician having left the bedside during withdrawal in 18 cases (48%) to attend other patients or to allow privacy for the family.</p> <p>Conclusions</p> <p>Wide case-by-case variation in timeframes occurs at every step of the process of withdrawal of life-sustaining treatment until death. This knowledge may facilitate medical management, clinical leadership, guidance of parents and inform organ procurement after cardiac death.</p

Ectomycorrhizal fungal communities in young forest stands regenerating after clearcut logging

The effects on the ectomycorrhizal fungal community of clearcut logging, which is used to harvest millions of hectares of ectomycorrhizal forest annually, has been studied for a number of years. Here, we review current knowledge of inoculum sources for ectomycorrhizal fungi in forests and then re-examine earlier studies of ectomycorrhizas on young trees in regenerating stands. We conclude that, taken separately from the effects of site preparation, the major impact of clearcut logging is to change the species composition of the ectomycorrhizal fungal community rather than to reduce the percentage of roots colonized. A thorough examination of site preparation treatments suggests that the changes in fungal species composition are driven by changes in the biology and chemistry of the soil environment after clearcutting as much as they are by loss or change in fungal inoculum. This is an important conclusion because it implies that these new ectomycorrhizal fungal communities are better adapted to the new conditions than the ones in the forest would have been. The shift in fungal species composition and diversity will have implications for seedling establishment and competition. The effects of individual fungi or diverse assemblages of fungi on seedling growth, and effects of changes in the ability of young trees to associate with a common mycelium are discussed

Ostectomía en Cuña de la Tibia como Tratamiento de la Rotura del Ligamento Cruzado Anterior. Estudio Retrospectivo

Analizar los resultados retrospectivos de 52 ostectomías en cuña de la tibia como tratamiento de la rotura del ligamento cruzado anterior. Específicos: • Caracterizar la población con rotura de ligamento cruzado anterior. • Describir los tipos de rotura y lesiones asociadas. • Calcular el ángulo de inclinación de la meseta tibial pre y post quirúrgico. • Analizar la evolución y resultados de la técnica de la ostectomía tibial en cuña