Biology

W

hile free-swimming microrobots have been explored as a way to precisely deliver therapeutics within a blood vessel, they can disperse in the strong flows, failing to reach their target at high enough concentrations. In contrast, microrobots propelled along an artificial microtubule, developed by physicist Arnold Mathijssen and colleagues, can be transported precisely, even working against the current. (Image: Courtesy of Arnold Mathijssen/Nature Machine Intelligence)

Reginald Kwarteng is an undergraduate student researcher in the Wagner Lab. (Image: Wil Prall)

When the enzyme DOT1L is not functional, spermatogonial stem cells become exhausted, leading to a failure of sperm cell development. This crucial role for DOT1L places it in rarefied company as one of just a handful of known stem cell self-renewal factors, a Penn Vet team found. (Image: Courtesy of Jeremy Wang)

A group of bacteriophages, viruses that infect bacteria, imaged using transmission electron microscopy. New research sheds light on how bacteria fight off these invaders without triggering an autoimmune response. (Image: ZEISS Microscopy, CC BY-NC-ND 2.0)

To commemorate Rare Disease Day, Magnolia Wang organized a lighting of the Pavilion of the Hospital of the University of Pennsylvania in support of the National Organization for Rare Disorders.

Like Alice furiously running to keep up with the Red Queen, but remaining in one place, two genetic elements in the fruit fly genome are engaged in an evolutionary arms race to simply keep the biological status quo, according to new research by Penn scientists. (Image: John Tenniel in Lewis Carroll’s Through the Looking Glass)

COVID-19’s hard-to-predict effects likely owe in part to genetic differences. A Penn-led study analyzing the genomes of a diverse set of populations globally points to genetic variants that may help explain some of the variability in disease severity.

After being transferred to an infertile mouse, testes tissue from a rat that had been frozen for more than two decades gave rise to sperm and germ cells. (Image: Eoin Whelan/PLOS Biology/CC-BY 4.0 https://creativecommons.org/licenses/by/4.0)

By studying how plants develop, Aman Husbands, who joined the Department of Biology faculty this year, may make insights that find application well beyond the plant kingdom.