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Bergstrom, D.

Publications and source records attributed to Bergstrom, D..

2 recordsLinked to original sources

Gaps and Advances in Long-Term Monitoring of Antarctic Near-Shore and Terrestrial Ecosystems

Environmental change due to greenhouse gas emissions is affecting ecosystems globally; in the polar regions in particular there is already significant evidence of change. The Antarctic Near-Shore and Terrestrial Observation System (ANTOS) aims to establish a cross-continent, cross-national observing network to assess environmental variability and change in the southern polar region. To understand how near-shore and terrestrial Antarctic ecosystems have and will continue to be impacted by anthropogenic environmental changes, a comprehensive review of current long-term monitoring efforts, and two surveys targeting Antarctic researchers, were carried out to evaluate existing monitoring efforts, environmental changes recorded, and to identify areas currently lacking sufficient observations. Results indicate that most data collection is manual and intra-annual, with significant long-term monitoring concentrated in regions with already established infrastructure. The surveys highlight the urgent need for comprehensive coverage of the Antarctics rapidly changing ecosystems using standardized monitoring protocols and increased collaboration. We recommend prioritizing areas experiencing rapid climatic changes and leveraging existing infrastructure to minimize environmental impact of monitoring activities and enhance data comparability across sites.

ecology↗

Identification of slow-cycling germline stem cells and their regulation by PLZF

Long-term maintenance of spermatogenesis in mammals is supported by GDNF, an essential growth factor required for spermatogonial stem cell (SSC) self-renewal. Exploiting a transgenic GDNF overexpression model, which expands and normalizes the pool of undifferentiated spermatogonia between Plzf+/+ and Plzflu/lu mice, we used RNAseq to identify a rare subpopulation of cells that express EOMES, a T-box transcription factor. Lineage tracing and busulfan challenge show that these are long-term SSCs that contribute to steady state spermatogenesis as well as regeneration following chemical injury. EOMES+ SSCs have a lower proliferation index than EOMES- GFRA1+ spermatogonia in wild-type but not in Plzflu/lu mice. This comparison demonstrates that PLZF regulates their proliferative activity and suggests that EOMES+ SSCs are lost through proliferative exhaustion in Plzflu/lu mice. Single cell RNA sequencing of EOMES+ cells from Plzf+/+ and Plzflu/lu mice support a hierarchical model of both slow- and rapid-cycling SSCs.

developmental biology↗