Isotopes from Fecal Material Provides Evidence of Recent Diet of Prairie Deer Mice

Prairie deer mice are important predators in many agricultural systems, and through their diet they can help to regulate pest insect and weed populations. Our objective was to test whether fecal material is an effective means of detailing the foraging ecology of small mammals. We conducted three studies to evaluate the efficacy of this technique: 1) field-collected fecal material from unknown deer mice from late winter to early spring, 2) fecal material collected in an enclosure with mice fed a mix of C3 and C4 plant seeds, and 3) fecal material from tagged female mice in the field. We detected significant shifts in δ13C in one study and δ15N in another relative to spring thaw (δ13C: –13.34 vs. –10.72, P = 0.01, δ15N: 4.92 vs. 4.09, P = 0.03), a significant correlation between the relative amounts of two seed types and δ13C (slope = 5.46, SE = 1.82, P \u3c 0.01), and a significant decrease in δ15N due to nursing (4.57 ± 0.19 vs 3.28 ± 0.47, P = 0.02). Use of this technique will help to clarify foraging of this economically important species in agroecosystems

Isotopes from Fecal Material Provides Evidence of Recent Diet of Prairie Deer Mice

Prairie deer mice are important predators in many agricultural systems, and through their diet they can help to regulate pest insect and weed populations. Our objective was to test whether fecal material is an effective means of detailing the foraging ecology of small mammals. We conducted three studies to evaluate the efficacy of this technique: 1) field-collected fecal material from unknown deer mice from late winter to early spring, 2) fecal material collected in an enclosure with mice fed a mix of C3 and C4 plant seeds, and 3) fecal material from tagged female mice in the field. We detected significant shifts in δ13C in one study and δ15N in another relative to spring thaw (δ13C: –13.34 vs. –10.72, P = 0.01, δ15N: 4.92 vs. 4.09, P = 0.03), a significant correlation between the relative amounts of two seed types and δ13C (slope = 5.46, SE = 1.82, P \u3c 0.01), and a significant decrease in δ15N due to nursing (4.57 ± 0.19 vs 3.28 ± 0.47, P = 0.02). Use of this technique will help to clarify foraging of this economically important species in agroecosystems

Potent CRISPR-Cas9 inhibitors from Staphylococcus genomes.

Anti-CRISPRs (Acrs) are small proteins that inhibit the RNA-guided DNA targeting activity of CRISPR-Cas enzymes. Encoded by bacteriophage and phage-derived bacterial genes, Acrs prevent CRISPR-mediated inhibition of phage infection and can also block CRISPR-Cas-mediated genome editing in eukaryotic cells. To identify Acrs capable of inhibiting Staphylococcus aureus Cas9 (SauCas9), an alternative to the most commonly used genome editing protein Streptococcus pyogenes Cas9 (SpyCas9), we used both self-targeting CRISPR screening and guilt-by-association genomic search strategies. Here we describe three potent inhibitors of SauCas9 that we name AcrIIA13, AcrIIA14, and AcrIIA15. These inhibitors share a conserved N-terminal sequence that is dispensable for DNA cleavage inhibition and have divergent C termini that are required in each case for inhibition of SauCas9-catalyzed DNA cleavage. In human cells, we observe robust inhibition of SauCas9-induced genome editing by AcrIIA13 and moderate inhibition by AcrIIA14 and AcrIIA15. We also find that the conserved N-terminal domain of AcrIIA13-AcrIIA15 binds to an inverted repeat sequence in the promoter of these Acr genes, consistent with its predicted helix-turn-helix DNA binding structure. These data demonstrate an effective strategy for Acr discovery and establish AcrIIA13-AcrIIA15 as unique bifunctional inhibitors of SauCas9

Perspectives of Extension Agents and Farmers Toward Multifunctional Agriculture in the United States Corn Belt

We surveyed the perspectives of farmers, crop professionals, and Extension agents and found that they have positive perspectives concerning multifunctional agriculture, including a positive effect of a nearby prairie to cropland productivity. The survey was conducted in central Iowa and included individuals predominantly from Iowa involved in commodity research and production. Our results are preliminary and provide a baseline for further research into the perspectives of change agents in the U.S. Corn Belt. They also provide insight into similarities among key links in the diffusion of innovation chain

Template coexistence in prebiotic vesicle models

The coexistence of distinct templates is a common feature of the diverse proposals advanced to resolve the information crisis of prebiotic evolution. However, achieving robust template coexistence turned out to be such a difficult demand that only a class of models, the so-called package models, seems to have met it so far. Here we apply Wright's Island formulation of group selection to study the conditions for the coexistence of two distinct template types confined in packages (vesicles) of finite capacity. In particular, we show how selection acting at the level of the vesicles can neutralize the pressures towards the fixation of any one of the template types (random drift) and of the type with higher replication rate (deterministic competition). We give emphasis to the role of the distinct generation times of templates and vesicles as yet another obstacle to coexistence.Comment: 7 pages, 8 figure

The College News, 1945-02-14, Vol. 31, No. 15

Bryn Mawr College student newspaper. Merged with The Haverford News in 1968 to form the Bi-college News (with various titles from 1968 on). Published weekly (except holidays) during the academic year