Project description:[original Title] Transcriptomic responses to heat-stress in invasive and native blue mussels (genus Mytilus): molecular correlates of invasive success. Invasive species are increasingly prevalent in marine ecosystems worldwide. Although many studies have examined the ecological effects of invasives, little is known about physiological mechanisms that might contribute to invasive success. The mussel Mytilus galloprovincialis, a native of the Mediterranean Sea, is a successful invader on the central and southern coasts of California, where it has largely displaced the native congener, Mytilus trossulus. It has been previously shown that thermal responses of several physiological traits may underlie the capacity of M. galloprovincialis to out-compete M. trossulus in warm habitats. To elucidate possible differences in stress-induced gene expression between these congeners, we developed an oligonucleotide microarray with 8,874 probes representing 4,488 different genes that recognized mRNAs of both species. In acute heat-stress experiments, 1,531 of these genes showed temperature-dependent changes in gene expression that were highly similar in the two congeners. In contrast, 96 genes showed species-specific responses to heat-stress, functionally characterized by their involvement in oxidative stress, proteolysis, energy metabolism, ion transport, cell signaling, and cytoskeletal reorganization. The gene that showed the biggest difference between the species was the gene for the molecular chaperone small heat shock protein 24, which was highly induced in M. galloprovincialis and showed only a small change in M. trossulus. These different responses to acute heat-stress may help to explain—and predict—the invasive success of M. galloprovincialis in a warming world.
Project description:The invasive marine mussel Mytilus galloprovincialis has displaced the native congener Mytilus trossulus from central and southern California, but the native species remains dominant at more northerly sites that have high levels of freshwater input. To determine the extent to which interspecific differences in physiological tolerance to low salinity might explain limits to the invasive species’ biogeography, we used an oligonucleotide microarray to compare the transcriptional responses of these two species to an acute decrease in salinity. Among 6,777 genes on the microarray, 117 genes showed significant changes that were similar between species, and 12 genes showed significant species-specific responses to salinity stress. Osmoregulation and cell cycle control were important aspects of the shared transcriptomic response to salinity stress, whereas the genes with species-specific expression patterns were involved in mRNA splicing, polyamine synthesis, exocytosis, translation, cell adhesion, and cell signaling. Forty-five genes that changed expression significantly during salinity stress also changed expression during heat stress, but the direction of change in expression was typically opposite for the two forms of stress. These results (i) provide insights into the role of changes in gene expression in establishing physiological tolerance to acute decreases in salinity, and (ii) indicate that transcriptomic differences between M. galloprovincialis and M. trossulus in response to salinity stress are subtle and involve only a minor fraction of the overall suite of gene regulatory responses.
Project description:Over the last 60 years, marine natural products have had major economic and commercial importance. The development of a National Marine Biodiscovery Laboratory in Ireland (NMBLI), located at the Marine Institute (Oranmore), aims to strengthen Ireland’s capacity as research leaders in marine biotechnology and in particularly marine natural products chemistry. The NMBLI houses an Irish marine repository derived from marine macro-organisms collected in Irish coastal waters. The aim of this project is to collect organisms for the marine repository and identify samples of interest for chemical investigation. Other than the development of the laboratory at the marine institute (Oranmore) with the appropriate facilities and procedure to undertake biodiscovery research, the outcomes of this project are to identify bioactive marine natural products from Irish marine life.
Project description:Vibrio species represent one of the most diverse genera of marine bacteria known for their ubiquitous presence in natural aquatic systems. Several members of this genus including Vibrio harveyi are receiving increasing attention lately because they are becoming a source of health problems, especially for some marine organisms widely used in sea food industry. To learn about adaptation changes triggered by V. harveyi during its long-term persistence at elevated temperatures, we studied adaptation of this marine bacterium in sea water microcosms at 30 oC that closely mimicks the upper limits of sea surface temperatures recorded around the globe.
Project description:The whitefly Bemisa tabaci is a species complex of more than 31 cryptic species which include some of the most destructive invasive pests of many ornamental and glasshouse crops worldwide. Among them, Middle East-Asia Minor 1 (herein MEAM1) and Mediterranean (herein MED) have invaded many countries around the world and displaced the native whitefly species. However, the molecular differences between invasive and indigenous whiteflies remain largely unknown. The global transcriptional difference between the two invasive whitefly Bemisia tabaci species (MEAM1, MED) and one indigenous whitefly species (Asia II 3) were analyzed using the Illumina sequencing technology.
Project description:In the present study, we were interested in gene expression changes in the pectoralis muscle of juvenile king penguins during the transition from terrestrial to marine life. Strictly terrestrial during their first year after hatching, king penguin chicks must then depart to sea to reach nutritional emancipation and pectoralis muscle is largely involved in penguin adaptation to the marine environment. To compare these transcriptomic profiles, we realized heterologous hybridization on Affymetrix GeneChip Chicken Genome Arrays, as the chicken is the closest model species for which microarrays are available. The development of a new algorithm, MaxRS, allow us to determine differentially expressed genes implicated in energetic metabolism or involved in cellular defense against reactive oxygen species and associated injuries. We compared muscle sample biopsy from 4 penguin juveniles captured just before they undergone their first immersion to cold water (named NI for Never Immersed) and 3 penguin juveniles that had completly accomplished their acclimation to marine life (named SA for Sea Acclimated).