Efforts in enrichment of novel photoautotroph identified through metagenomics
Abstract: Aerobic anoxygenic phototrophs are ubiquitous throughout the global ocean, making up to 11% of the community in some locations. Traditionally aerobic anoxygenic phototrophs have been associated with photoheterotrophy while anaerobic anoxygenic phototrophs were associated with facultative photoautotrophy. Using draft genomes generated from the Tara Oceans metagenomic dataset, 11 draft genomes were identified that lacked key genes for survival in suboxic environments and possessed key genes with the potential for anoxygenic phototrophy via Type-II photochemical reaction centers, carbon fixation via the Calvin-Benson-Bassham cycle, and lithotrophic energy utilization via the oxidation of sulfite and/or thiosulfate. To further study this group and characterize its carbon fixation capability and metabolism there is a need to enrich or isolate the organism. Here we have used comparative genomics to predict the potential metabolism and designed a low nutrient autotrophic medium to enrich for this group using sea water collected at the surface from the San Pedro Ocean Time series (SPOT).
JOSH KLING (PI: Prof. David Hutchins and Prof. Feixue Fu)
Thermal Diversity in a Coastal Marine Synechoccus Population Selected Under Low- and High Temperatures
Abstract: Synechococcus is a photoautroph found from the equator to near polar waters and contributes together with other picocyanobacteria as much as 25% of net primary productivity in the ocean. The effect of temperature on intraspecific Synechococcus diversity and evolution is well documented; however, it is usually expressed as changing the distribution and relative abundance of distinct clades. To probe for diverse phenotypes, we enriched for photoautotrophs from water collected at the Narragansett Bay Time-series and grown at unseasonably low (18° C) and high (30°) temperatures. From these enrichments, we isolated multiple Synechococcus sp. and quantified their thermal niche by generating thermal performance curves for each, which revealed distinct thermotypes characterized by different maximum temperature limits and optimal temperatures. To understand the genotypic diversity underlying observed phenotypic diversity, we sequenced the genomes of 8 strains, and we found evidence that suggests that variation in genes underlying accessory photosynthetic pigments appears to be related to thermal phenotype in our Synechococcus strains.
JASON WANG (PI: Prof. Donal Manahan)
Challenges with linking genes to organismal function
Abstract: The leading edge of biological discovery is enabled by a limited number of “model” organisms, with sophisticated resources for the study of genes and their function. Studies of most organisms, however, lack such resources, in particular for the study of functional genomics. The increasing availability of completed genomes and the use of biotechnology in “non-model” organisms offer new opportunities to bridge gaps in understanding biological function, from genes to the whole-organism. I will present some recent steps taken to understand the function of an expanded set of orthologous genes that have been identified in developmental stages of marine invertebrates. These studies have implications for understanding the molecular biological basis of nutrient uptake, with predicting links to whole-organism growth rates.
12 PM
AHF 153 (Torrey Webb Room)
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