Functional diversity in resource use by fungi.

Fungi influence nutrient cycling in terrestrial ecosystems, as they are major regulators of decomposition and soil respiration. However, little is known about the substrate preferences of individual fungal species outside of laboratory culture studies. If active fungi differ in their substrate preferences in situ, then changes in fungal diversity due to global change may dramatically influence nutrient cycling in ecosystems. To test the responses of individual fungal taxa to specific substrates, we used a nucleotide-analogue procedure in the boreal forest of Alaska (USA). Specifically, we added four organic N compounds commonly found in plant litter (arginine, glutamate, lignocellulose, and tannin-protein) to litterbags filled with decomposed leaf litter (black spruce and aspen) and assessed the responses of active fungal species using qPCR (quantitative polymerase chain reaction), oligonucleotide fingerprinting of rRNA genes, and sequencing. We also compared the sequences from our experiment with a concurrent warming experiment to see if active fungi that targeted more recalcitrant compounds would respond more positively to soil warming. We found that individual fungal taxa responded differently to substrate additions and that active fungal communities were different across litter types (spruce vs. aspen). Active fungi that targeted lignocellulose also responded positively to experimental warming. Additionally, resource-use patterns in different fungal taxa were genetically correlated, suggesting that it may be possible to predict the ecological function of active fungal communities based on genetic information. Together, these results imply that fungi are functionally diverse and that reductions in fungal diversity may have consequences for ecosystem functioning

Parallel laboratory evolution and rational debugging reveal genomic plasticity to S. cerevisiae synthetic chromosome XIV defects

Synthetic chromosome engineering is a complex process due to the need to identify and repair growth defects and deal with combinatorial gene essentiality when rearranging chromosomes. To alleviate these issues, we have demonstrated novel approaches for repairing and rearranging synthetic Saccharomyces cerevisiae genomes. We have designed, constructed, and restored wild-type fitness to a synthetic 753,096-bp version of S. cerevisiae chromosome XIV as part of the Synthetic Yeast Genome project. In parallel to the use of rational engineering approaches to restore wild-type fitness, we used adaptive laboratory evolution to generate a general growth-defect-suppressor rearrangement in the form of increased TAR1 copy number. We also extended the utility of the synthetic chromosome recombination and modification by loxPsym-mediated evolution (SCRaMbLE) system by engineering synthetic-wild-type tetraploid hybrid strains that buffer against essential gene loss, highlighting the plasticity of the S. cerevisiae genome in the presence of rational and non-rational modifications. </p

Extra embryos: The ethics of cryopreservation in Ecuador and elsewhere

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73714/1/ae.2007.34.1.181.pd

Divergence of the Yeast Transcription Factor FZF1 Affects Sulfite Resistance

Changes in gene expression are commonly observed during evolution. However, the phenotypic consequences of expression divergence are frequently unknown and difficult to measure. Transcriptional regulators provide a mechanism by which phenotypic divergence can occur through multiple, coordinated changes in gene expression during development or in response to environmental changes. Yet, some changes in transcriptional regulators may be constrained by their pleiotropic effects on gene expression. Here, we use a genome-wide screen for promoters that are likely to have diverged in function and identify a yeast transcription factor, FZF1, that has evolved substantial differences in its ability to confer resistance to sulfites. Chimeric alleles from four Saccharomyces species show that divergence in FZF1 activity is due to changes in both its coding and upstream noncoding sequence. Between the two closest species, noncoding changes affect the expression of FZF1, whereas coding changes affect the expression of SSU1, a sulfite efflux pump activated by FZF1. Both coding and noncoding changes also affect the expression of many other genes. Our results show how divergence in the coding and promoter region of a transcription factor alters the response to an environmental stress

Developing Digital Clinical Simulations for Large-Scale Settings on Diversity, Equity, and Inclusion: Design Considerations for Effective Implementation at Scale

Digital clinical simulations (DCSs) are a promising tool for professional learning on diversity, equity, and inclusion (DEI) issues across a variety of fields. Although digital clinical simulations can be integrated into large-scale learning environments, less is known about how to design these types of simulations so they can scale effectively. We describe the results of two studies of a digital clinical simulation tool called Jeremy's Journal. In Study 1, we implemented this simulation in an in-person workshop with a human facilitator. We found that participants described their learning experiences positively and reported changes in attitudes. In Study 2, we used the simulation within an online course but replaced the human facilitator with an asynchronous, text-based adaptation of the facilitation script. Although learners in Study 2 described the experience in the simulation positively, we did not observe changes in attitudes. We discuss the implications of these findings for the design of DCSs at scale

Measuring Equity-Promoting Behaviors in Digital Teaching Simulations: A Topic Modeling Approach

Diversity, equity, and inclusion (DEI) issues are urgent in education. We developed and evaluated a massive open online course ( N = 963) with embedded equity simulations that attempted to equip educators with equity teaching practices. Applying a structural topic model (STM)—a type of natural language processing (NLP)—we examined how participants with different equity attitudes responded in simulations. Over a sequence of four simulations, the simulation behavior of participants with less equitable beliefs converged to be more similar with the simulated behavior of participants with more equitable beliefs ( ES [effect size] = 1.08 SD). This finding was corroborated by overall changes in equity mindsets ( ES = 0.88 SD) and changed in self-reported equity-promoting practices ( ES = 0.32 SD). Digital simulations when combined with NLP offer a compelling approach to both teaching about DEI topics and formatively assessing learner behavior in large-scale learning environments. </jats:p