A Small Molecule – Protein Hybrid for Voltage Imaging via Quenching of Bioluminescence

We report a small molecule enzyme pair for optical voltage sensing via quenching of bioluminescence. This Quenching Bioluminescent Voltage Indicator, or Q-BOLT, pairs the dark absorbing, voltage-sensitive dipicrylamine with membrane-localized bioluminescence from the luciferase NanoLuc (NLuc). As a result, bioluminescence is quenched through resonance energy transfer (QRET) as a function of membrane potential. Fusion of HaloTag to NLuc creates a two-acceptor bioluminescence resonance energy transfer (BRET) system when a tetramethylrhodamine (TMR) HaloTag ligand is ligated to HaloTag. In this mode, Q-BOLT is capable of providing direct visualization of changes in membrane potential in live cells via three distinct readouts: change in QRET, BRET, and the ratio between bioluminescence emission and BRET. Q-BOLT can provide up to a 29% change in bioluminescence (ΔBL/BL) and >100% ΔBRET/BRET per 100 mV change in HEK 293T cells, without the need for excitation light. In cardiac monolayers derived from human induced pluripotent stem cells (hiPSC), Q-BOLT readily reports on membrane potential oscillations. Q-BOLT is the first example of a hybrid small molecule – protein voltage indicator that does not require excitation light and may be useful in contexts where excitation light is limiting. </p

Availability of Tanning Beds on US College Campuses

Importance: Indoor tanning is widespread among young adults in the United States despite evidence establishing it as a risk factor for skin cancer. The availability of tanning salons on or near college campuses has not been formally evaluated. Objective: To evaluate the availability of indoor tanning facilities on US college and university campuses (colleges) and in off-campus housing surrounding but not owned by the college. Design, Setting, and Participants: This observational study sampled the top 125 US colleges and universities listed in US News and World Report. Investigators searched websites of the colleges and nearby housing and contacted them by telephone inquiring about tanning services. Main Outcomes and Measures: Frequency of indoor tanning facilities on college campus and in off-campus housing facilities, as well as payment options for tanning. Results: Of the 125 colleges, 48.0% had indoor tanning facilities either on campus or in off-campus housing, and 14.4% of colleges allow campus cash cards to be used to pay for tanning. Indoor tanning was available on campus in 12.0% of colleges and in off-campus housing in 42.4% of colleges. Most off-campus housing facilities with indoor tanning (96%) provide it free to tenants. Midwestern colleges had the highest prevalence of indoor tanning on campus (26.9%), whereas Southern colleges had the highest prevalence of indoor tanning in off-campus housing facilities (67.7%). Presence of on-campus tanning facilities was significantly associated with enrollment (P=.01), region (P=.02), and presence of a school of public health (P=.01) but not private vs public status (P=.18) or presence of a tobacco policy (P=.16). Presence of tanning facilities in off-campus housing was significantly associated with region (P=.002) and private vs public status (P=.01) but not enrollment (P=.38), tobacco policy (P=.80), or presence of a school of public health (P=.69). Conclusions and Relevance: Reducing the availability of indoor tanning on and around college campuses is an important public health target

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<p>Changes in iron (Fe) bioavailability influence diatom physiology and community composition, and thus have a profound impact on primary productivity and ecosystem dynamics. Iron limitation of diatom growth rates has been demonstrated in both oceanic and coastal waters of the Northeast Pacific Ocean and is predicted to become more pervasive in future oceans. However, it is unclear how the strategies utilized by phytoplankton to cope with low Fe bioavailability and resupply differ across these ocean provinces. We investigated the response of diatom communities to variable Fe conditions through incubation experiments performed in the Fe mosaic of the California Upwelling Zone and along a natural Fe gradient in the Northeast Pacific Ocean. Through coupling gene expression of two dominant diatom taxa (Pseudo-nitzschia and Thalassiosira) with biological rate process measurements, we provide an in-depth examination of the physiological and molecular responses associated with varying Fe status. Following Fe enrichment, oceanic diatoms showed distinct differential expression of gene products involved in nitrogen assimilation, photosynthetic carbon fixation, and vitamin production compared to diatoms from low-Fe coastal sites, possibly driven by the chronic nature of Fe stress at the oceanic site. Genes of interest involved in Fe and N metabolism additionally exhibited divergent expression patterns between the two diatom taxa investigated, demonstrating that diverse diatoms may invoke alternative strategies when dealing with identical changes in their environment. We report here several mechanisms used distinctly by coastal or oceanic diatom communities as well as numerous taxa-specific strategies for coping with Fe stress and rearranging nutrient metabolism following Fe enrichment.</p