| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | September 28, 2011 |
| Latest Amendment Date: | February 18, 2015 |
| Award Number: | 1129119 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Donald L. Rice
OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | September 15, 2011 |
| End Date: | June 30, 2015 (Estimated) |
| Total Intended Award Amount: | $241,256.00 |
| Total Awarded Amount to Date: | $241,256.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
2425 CAMPUS RD SINCLAIR RM 1 HONOLULU HI US 96822-2247 (808)956-7800 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
3190 Maile Way Honolulu HI US 96822-2243 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Chemical Oceanography |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
In this project an interdisciplinary research team from the University of Hawaii at Manoa, Stanford University, and Rutgers University will study the transcriptomes of Gambierdiscus, Staphylococcus aureus, and Enterococcus in Hawaiian coastal waters - toxin-producing species that pose significant health hazards to humans. Their goal is to elucidate the mechanisms associated with toxin production by Gambierdiscus and inactivation by sunlight of the bacterial pathogen, S. aureus, and the fecal indicator, Enterococcus. Because the transcriptome of an organism reflects the genes that are actively being expressed at any given time, this study, by elucidating levels of messenger RNA expression in the target organisms, should provide valuable insights into the mechanisms responsible for toxin production, responses to stress and/or subsequent bacterial inactivation.
The research program will be organized around four working hypotheses:
H1: Production of ciguatoxin by Gambierdiscus reflects the physiological condition of the culture as influenced by temperature, irradiance, and growth phase.
H2: High throughput transcriptome analysis from toxin (+) and toxin (-) cultures will allow the identification of genes involved in ciguatoxin production and understanding of the light and nutrient conditions that favor this function.
H3: Whereas E. faecalis is susceptible to indirect photoinactivation under exposure to sunlight in seawater, S. aureus is not. This is likely due to the presence of carotenoid pigments within the cells, which are able to quench reactive oxygen species.
H4: E. faecalis and S. aureus respond to photo-stress in clear seawater by up-regulating genes that encode for proteins to repair cellular damage and mitigate oxidative stress; this "stressome" will change with increasing exposure to photostress, revealing the stress at which repair is no longer possible.
Broader Impacts: The information that will be gathered in this study is expected to contribute significantly to advancing the field of risk management with respect to recreational water use and seafood consumption beyond reliance on empirical correlations and towards policies that are based on a mechanistic understanding of the threats these organisms pose to human health.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
In overview, this research sought to determine whether and to what extent changes of physic-chemical parameters that control photosynthetic dinoflagellates (e.g., Gambierdiscus spp.) that produce ciguatoxin precursor molecules are reflected in changes in the gene expression within Gambierdiscus spp. over the range of tolerance limits for physic-chemical parameters (e.g., temperature, salinity, irradiance, nutrient status, culture growth state.) The primary obstacle to be overcome is that the genome of dinoflagellates such as Gambierdiscus are huge, and this creates difficulty in identifying the portion of genome that may be responding differently to a particular physico-chemical regime. The team performed the cytotoxicity analyses, and then attempted to identify that portion of the genome may be associated with cytotoxicity changes caused by changes in the culture environment. To conduct this study, the research team isolated and cultured Gambierdiscus caribaeus, isolated from Hawaiian coastal waters, under a range of temperature, salinity, and irradiation regimes that embrace the tolerances limits of this species for CTX assessments. The intent was to determine whether and to what extent changes of physic-chemical parameters are coupled with changes in cell-specific quotas of toxicity and whether such changes may be associated with changes in their transcriptomic signatures. The ultimate usefulness of this research is to better understand the conditions which are most associated with high levels of toxin production so that the public may be better informed as to when fish harvesting may be especially hazardous. Portions of the research findings were communicated in presentations to both technical and lay public audiences, and via publications presentations, and a public-oriented website. The performance of this research involved the mentoring of a number of undergraduate students many of whom were from ethnicities that are under-represented in the science and technology fields.
Last Modified: 08/12/2015
Modified by: Paul K Bienfang
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