Biology subjects

Harrison, E.

Publications and source records attributed to Harrison, E..

21 records · Page 2Linked to original sources

bioRxiv2020

A novel Ca2+ signalling pathway co-ordinates environmental phosphorus sensing and nitrogen metabolism in marine diatoms

Diatoms are a diverse and globally important phytoplankton group, responsible for an estimated 20% of carbon fixation on Earth. They frequently form spatially extensive phytoplankton blooms, responding rapidly to increased availability of nutrients including phosphorus and nitrogen. Although it is well established that diatoms are common first-responders to nutrient influxes in aquatic ecosystems, little is known of the sensory mechanisms that they employ for nutrient perception. Here we show that diatoms use a novel and highly-sensitive Ca2+-dependent signalling pathway, not previously described in eukaryotes, to sense and respond to the critical macronutrient phosphorus. We demonstrate that phosphorus-Ca2+ signalling is essential for regulating diatom recovery from phosphorus limitation, by controlling rapid and substantial increases in nitrogen assimilation. Phosphorus-Ca2+ signalling thus mediates fundamental cross-talk between the vital nutrients P and N to maximise resource competition, and likely governs the success of diatoms as major bloom formers in regions of pulsed nutrient supply. Importantly, our study demonstrates that distinct mechanisms for nutrient sensing have evolved in photosynthetic eukaryotes.

microbiology↗

bioRxiv2019

Education influences knowledge about environmental issues in Washington, DC, USA

We predicted that demographic differences in Washington, DCs population would influence peoples knowledge and perceptions about the interconnectedness of natural resources, climate change, economics, and socio-cultural well-being, so we conducted surveys over three years to test that prediction. We collected demographic data from 455 participants and asked them 26 questions/statements related to natural resources, climate change, economics, and health. We selected education as the focal demographic category and participants were categorized based on their level of educational attainment: 1) completion of high school or less (hereafter \"high school\"); 2) some trade school or university education beyond high school up to and including completion of a trade school, two-, or four-year degree (hereafter \"post-high school\"); and 3) completion of a Masters, professional, or doctoral degree (hereafter \"advanced education\"). Answers to 14 of the 26 survey questions were dissimilar across educational groups. People with advanced education reported the highest connection with the natural community and were more likely to report that their personal welfare depended on the natural community. Participants in the high school group were more likely to believe that humans do not have much influence on natural resources and placed more trust in technology and human achievements to control nature and ensure that earth will not become unlivable. Compared to those with education beyond high school, those with a high school education were more likely to express an interest in local environmental concerns over global, jobs over natural resources, and effects of degraded local natural resources on income, health, and the environment instead of on cultural/social practices, neighborhood aesthetics, and recreation. The results suggest ways in which educational information and engagement in environmental issues should be targeted for stakeholders of different educational background in order to increase knowledge and build effective partnerships that find solutions for environmental problems.

ecology↗

bioRxiv2018

Patterns of recurrence after curative-intent surgery for pancreas cancer reinforce the importance of locoregional control and adjuvant chemotherapy.

IntroductionThe pattern of recurrence after surgical excision of pancreas cancer may guide alternative pre-operative strategies to either detect occult disease or need for chemotherapy. This study investigated patterns of recurrence after pancreatic surgery.\n\nMethodsRecurrence patterns were described in a series of resected pancreas cancers over a 2-year period and recurrence risk expressed as odds ratio (OR) with 95% confidence interval (C.I.). Survival was displayed by Kaplan-Meier curves.\n\nResultsOf 107 pancreas resections, 69 (65%) had pancreatic cancer. R0 resection was achieved in 21 of 69 (30.4%). Analysis was based on 66 patients who survived 30 days after surgery with median follow up 21 months. Recurrence developed in 41 (62.1%) patients with median time to first recurrence of 13.3 months (interquartile range 6.9, 20.8 months). Recurrence site was most frequently locoregional (n=28, 42%), followed by liver (n=23, 35%), lymph nodes (n=21, 32%), and lungs (n=13, 19%). In patients with recurrence, 9 of 41 had single site recurrence; the remaining 32 patients had more than one site of recurrence. Locoregional recurrence was associated with R+ resection (53% vs 25% for R+ vs R0, respectively; OR 3.5, 95% C.I. 1.1-11.2; P=0.034). Venous invasion was associated with overall recurrence risk (OR 3.3, 95% C.I. 1.1-9.4; P=0.025). In multivariable analysis, R-stage and adjuvant chemotherapy predicted longer survival.\n\nDiscussionThe predominant locoregional recurrence pattern, multiple sites of recurrence and a high R+ resection rate reflect the difficulty in achieving initial local disease control.

pathology↗