- Sacha Vignieri
As the human population has grown and spread, conflict between human activities, especially agriculture, and wildlife have become increasingly damaging and unsustainable. Policies that both legally protect wildlife populations and subsidize farmers for allocating resources to wildlife can help to mitigate these conflicts. Eythórsson et al. evaluate the Norwegian portion of a plan put in place to reduce conflict between pink-footed geese (Anser brachyrhynchus) and farmers along the goose's northern flyway. They found that local organization of farmers and subsidies contributed to the success of the plan, especially when reimbursements were corrected to be more directly related to damages. However, top-down input (in the form of the intercountry species management plan) was also deemed essential for ensuring that the focus remained on goose conservation, as opposed to farmer reimbursement. Their analysis demonstrates the importance of combining transparency for stakeholders and strict enforcement for species conservation in efforts to facilitate species persistence in the face of human land use.
Ambio 10.1007/s13280-016-0884-4 (2017).
- Cancer Treatment
Countering chemo's effects on fertility
- Paula A. Kiberstis
Conventional chemotherapy with DNA-damaging agents has helped countless cancer patients become cancer survivors. This successful outcome is sometimes accompanied by long-term side effects, however. In young female patients, for example, the alkylating agent cyclophosphamide can compromise fertility. This occurs because the drug causes inappropriate activation of ovarian follicular development, thereby exposing oocytes to its DNA-damaging effects. Studying a mouse model, Goldman et al. showed that ovarian function and fertility are preserved when cyclophosphamide is coadministered with drugs called mTORC1/2 inhibitors, which suppress a signaling pathway required for follicular activation. mTORC1/2 inhibitors are already clinically approved for other purposes, including treatment of certain forms of breast cancer, and may merit exploration as a fertility-preserving strategy in female cancer patients.
Proc. Natl. Acad. Sci. U.S.A. 114, 3186 (2017).
The physics of social butterflies
- Melissa McCartney
As science education moves toward more active classes, what can we learn about how student socialization affects learning? Zwolak et al. used social network analysis to investigate the academic and social experiences of students in an introductory Modeling Instruction (active learning) physics course. Students were asked to list the names of fellow students with whom they had a meaningful interaction five times throughout the semester. Using centralities, which are measures of position within the social network, intrapersonal interactions between students were quantified. Results showed that students with a higher centrality at the end of the semester were more likely to persist in physics (i.e., continue through the sequence of courses), suggesting that social integration may help in keeping students in science, technology, engineering, and math disciplines.
Phys. Rev. Phys. Educ. Res. 10.1103/PhysRevPhysEducRes. 13.010113 (2017).
The eyes have it
- Sacha Vignieri
Around 385 million years ago, aquatic tetrapods colonized terrestrial environments. We know much about the limb development that this shift from a buoyant to a weight-bearing existence required and shaped, but much less about how these animals managed the equally different sensory challenge of above-water living. MacIver et al. used phylogenetic approaches to document considerable expansions in eye size that occurred well before land colonization. Further, computational explorations of visual acuity show that these expansions, though not particularly helpful for improving underwater vision, would have conferred vast visual improvements in air. The changes likely occurred as a result of a crocodilian-type lifestyle wherein aquatically adapted species floated and foraged on the surface—a lifestyle that both preceded, and prepared species for, subsequent colonization of the terrestrial realm.
Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1615563114 (2017).
- Cellular Responses
Disordered proteins make a dynamic switch
- L. Bryan Ray
The proteins that regulate cellular responses to hypoxia form a sensitive on-off switch. Cells survive hypoxia by activating the transcription factor HIF-1α (hypoxia-inducible factor 1α). HIF-1α is active when it is associated with the transcriptional coactivator CBP. The protein CITED2 opposes such activation. CITED2 and HIF-1α bind overlapping regions of CBP with similar affinity. But CITED2 can much more effectively displace HIF-1α from CBP and inhibit transcription. The flexibility of intrinsically disordered regions of CITED2 apparently allows it to slip in and cause an allosteric change in CBP that hinders interaction with HIF-1α. Other such switches may exist, and in such cases, modeling on the basis of binary dissociation constants would be very misleading.
Nature 10.1038/nature21705 (2017).
Setting up a recruiting office
- Marc S. Lavine
The successful growth of large tissues requires the formation of a vascular system to ensure the proper supply of nutrients to the growing cells. One route to angiogenesis in the growing tissue is through the delivery of growth factors such as VEGF, but clinically this method has limitations. An alternative is to harness proangiogenic cells, such as blood-derived CD133+ cells, also known as circulating angiogenic cells (CACs). Parlato et al. used a cell invasion assay to optimize a hydrogel designed to recruit CACs over a period of 24 hours. Although hydrogel degradability and hydrogel stiffness—two known variables often connected with cell behavior—were found to be important in attracting CACs, a key third factor was the presentation of a gradient of stromal derived factor 1.
Acta Biomat. 10.1016/j.actbio.2017.03.048 (2017).
Nanostructured high-strength alloys
- Brent Grocholski
Low-density magnesium alloys are a promising type of material for making lighter vehicles and improving fuel efficiency. One challenge for lightweighting is developing high-strength magnesium alloys. Wu et al. created a dual-phase magnesium thin film with near-ideal strength. The alloy consists of small nanocrystalline cores surrounded by glass, combining the benefits of both phases to create the high-strength alloy. The strategy for creating this type of nanostructure should translate to other types of alloys, opening a different pathway to creating high-strength metals.
Nature 10.1038/nature21691 (2017).