Stressed Induced Changes in <i>Karenia brevis</i> Ribosomal RNA

<p><em>Karenia brevis</em> is a toxic marine dinoflagellate that causes harmful algal blooms (HABs), also known as red tides, in the Gulf of Mexico. These blooms are responsible for massive fish kills, shellfish bed contaminations, adverse human health effects, and vast economic loss. For these reasons, extensive research has gone into understanding the mechanisms and dynamics of bloom behavior by studying <em>K. brevis</em> in the field and in the lab. In order to understand higher order bloom behavior and dynamics it is imperative to understand <em>K. brevis</em> at the cellular level. In growing <em>K. brevis</em> in vitro under a variety of conditions, we have noted a distinct shift in the size of both ribosomal RNAs upon culturing cells under “stress” conditions, namely nutritional stress, cold shock, and decreased salinity. When the total RNA is extracted we have detected aberrant rRNA bands on the microcapillary electrophoresis BioAnalyzer (Agilent, Inc.) Interestingly when stressed, the large ribosomal subunit (LSU) becomes larger in size, and the small ribosomal subunit (SSU) becomes smaller. The initial hypothesis was that these aberrant bands were from some intracellular organism which was escaping a dying host. Through microscopy we were not able to support this hypothesis. Subsequently we also considered this response to be something <em>K. brevis </em>does in response to stress. This response by <em>K. brevis</em> had not been previously described in the literature. RNAs, pre- and post-stress, are being fully sequenced to determine how they are different, and what mechanisms may be responsible for producing them: alternative splicing, different transcriptional initiation or termination sites, or different loci? These results will help us understand the molecular events surrounding <em>K. brevis </em>survival under certain environmental conditions, which may have implications regarding <em>K. brevis</em> biogeographical distribution and bloom termination.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Discipline thesis:degree_discipline

Biological Sciences

Year dc:date.available

2015

Author dc:creator

• Jayroe, David Scott

Contributors dc:contributor

• Shahid Karim
• Tim McLean
• Glen Shearer

• Karenia brevis
• stress
• rRNA changes
• HAB
• Bioinformatics
• Integrative Biology
• Marine Biology
• Microbiology

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/104

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-1108