Biophysical Society Newsletter - July 2015

14

BIOPHYSICAL SOCIETY NEWSLETTER

2015

JULY

Subgroups

further improve our understanding of the physi- cochemical environment in the cell – there is still much to learn about the cell interior which cannot be extracted from the genome but is crucial for life! BIV Subgroup Store Need to commemorate the achievement of a lab group member or colleague? Consider buying a unique gift from the BIV Subgroup Store! (http:// www.zazzle.com/biopolymers_in_vivo) — Daryl K. Eggers , Subgroup Secretary-Treasurer Grants and Opportunities East Asia and Pacific Summer Institutes for U.S. Graduate Students (EAPSI) Objective: To provide U.S. graduate students in science, engineering, and education first-hand research experiences in Australia, China, Japan, Korea, New Zealand, Singapore, or Taiwan; an introduction to the science, science policy, and scientific infrastructure of the respective location; and an orientation to the society, culture, and language.

BIV An interview with Arnold Boersma , a research fellow at the University of Groningen and co-cor- responding author on the paper, A Sensor for Mac- romolecular Crowding in Living Cells , A.J. Boersma, I.S. Zuhorn, and B. Poolman; Nat Methods , 2015, 12: 227-229. Arnold, could you describe the molecular components of your sensor? The crowding sensor consists of three parts, two fluorescent proteins connected by a flexible linker that includes two stable helices. The fluorescent proteins form a FRET pair, allowing one to monitor the size (com- pactness) of the molecule in response to crowding effects. What experiment convinced you that the sensor is responding to changes in excluded volume? The FRET signal increases with increasing size or amount of added polymers like Ficoll, but the cor- responding monomers ( e.g. sucrose) do not change the signal, ruling out direct chemical interactions. How were the measurements obtained with living cells? The intensities of the emission of the FRET donor and acceptor were determined by confocal microscopy. Taking into account auto- fluorescence from the cells, the ratio of the two fluorophores was determined after splitting the emission into two channels. How did you alter the extent of crowding, and what was the result? We increased the osmolar- ity of the medium which leads to dehydration of the cells and an increase in crowding. When we tested the sensor under these conditions, we indeed observed an increase in the FRET signal, which diminished when we allowed the cells to adapt to the osmotic stress. What next? This research was done as part of a grant aimed at developing an independent line of research, hosted in Bert Poolman’s laboratory. Next, I’m planning to continue on this path and

Arnold Boersma

Deadline: November 12, 2015

Website: www.nsf.gov/funding/pgm_summ. jsp?pims_id=5284

The Sunnybrook Research Prize

Objective: Student should be in third or fourth year of study at a Canadian university by Fall 2015 and have completed a research project with a focus on biomedical research.

Deadline: October 29, 2015

Website: http://sunnybrook.ca/research/ content/?page=sri-ed-undergrad-prize