Linking Genes to Traits in Fungi.

Fungi are mediators of the nitrogen and carbon cycles in terrestrial ecosystems. Examining how nitrogen uptake and organic matter decomposition potential differs in fungi can provide insight into the underlying mechanisms driving fungal ecological processes and ecosystem functioning. In this study, we assessed the frequency of genes encoding for specific enzymes that facilitate nitrogen uptake and organic matter decomposition in 879 fungal genomes with fungal taxa grouped into trait-based categories. Our linked gene-trait data approach revealed that gene frequencies vary across and within trait-based groups and that trait-based categories differ in trait space. We present two examples of how this linked gene-trait approach can be used to address ecological questions. First, we show that this type of approach can help us better understand, and potentially predict, how fungi will respond to environmental stress. Specifically, we found that trait-based categories with high nitrogen uptake gene frequency increased in relative abundance when exposed to high soil nitrogen enrichment. Second, by comparing frequencies of nitrogen uptake and organic matter decomposition genes, we found that most ectomycorrhizal fungi in our dataset have similar gene frequencies to brown rot fungi. This demonstrates that gene-trait data approaches can shed light on potential evolutionary trajectories of life history traits in fungi. We present a framework for exploring nitrogen uptake and organic matter decomposition gene frequencies in fungal trait-based groups and provide two concise examples on how to use our framework to address ecological questions from a mechanistic perspective.

Physician reluctance to discuss advance directives. An empiric investigation of potential barriers.

BACKGROUND: To determine the relative impact of five proposed barriers to physician usage of advance directives with the aim of increasing the number of advance directives generated. METHODS: Questionnaires were sent to 460 internal medicine resident and attending physicians at a large New York, NY, hospital. Of these, 277 (60%) responded. We used multiple regression to measure the impact of five barriers to physician-initiated discussions of advance directives (time constraints, compensation concerns, discomfort with the subject, beliefs about appropriateness, and lack of understanding) on respondents' estimates of the number of advance directives held by respondents' patients, the number of recent advance directive discussions, and the number of discussions initiated by physicians. RESULTS: Physician lack of understanding and erroneous beliefs about appropriateness had particularly strong effects, serving as barriers to recent advance directive discussions (P < .0001 and P < .0001, respectively) and total number of advance directives held (P < .0001 and P < .02). Physicians' lack of knowledge also served as a barrier to the percentage of discussions that were physician initiated (P < .003 and P < .04). Time constraints and lack of comfort affected only discussions that were physician initiated (P < .001). Compensation concerns did not appear to serve as a barrier. Respondents were supportive of the concept of advance directives but reported minimal use of them in appropriate situations. CONCLUSIONS: Attention can now be focused on methods to overcome the five barriers studied and thereby enhance the execution of advance directives.