Coastal habitats & Salt Lakes
Euryhaline aquatic animals have mainly evolved in two extreme environments: coastal habitats (the intertidal zone and estuaries) and arid habitats (desert lakes, ponds, and creeks) . These environments are characterized by fluctuating salinity. Besides salinity stress, they also impose temperature, oxidative, and other types of stress on organisms. Examples of such habitats include coastal lagoons in California and elsewhere , the California Salton Sea , and Salt Creek in Death Valley . Primitive animals (rotifers, tardigrades, and nematodes) are even found in the diverse ponds of Bratina Island in the Dry Valleys region of Antarctica . Organisms inhabiting these environments are often eurytolerant, i.e. tolerant towards multiple environmental stressors. We are studying the underlying molecular basis for such environmental stress cross-tolerance. The goal is to know how many and which genes and proteins need to undergo evolutionary change to confer high environmental stress tolerance in aquatic animals. Such knowledge informs us about the time scale and mechanistic prerequisites that are necessary and sufficient for adaptation of aquatic organisms to salinity and temperature stress. Hence, this research will reveal animal coping strategies that have a selective advantage during anthropogenically accelerated climate change.
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Stress proteome evolution
Evolution has given rise to fish species that are uniquely adapted to a wide variety of most extreme habitats. We study the biochemical and evolutionary mechanisms that facilitate such adaptation . We aim to better understand how the minimal stress proteome has evolved to interact with other proteins to facilitate high environmental stress tolerance in euryhaline fish . The ultimate goal of our research is to decipher the logic by which stress-responsive signaling networks control transcriptional and proteome regulatory networks . Comparative studies of these networks in euryhaline and stenohaline species reveals targets of evolution when environmental salinity stress represents a major selection pressure. To transform correlational networks into causality networks our approaches are based primarily on molecular phenotyping (quantitative proteomics, SWATH mass spectrometry ) and functional genomics (gene targeting, genome editing ). The proteome represents the sum of expressed proteins in a given tissue at a particular time. It signifies the ultimate link connecting the genomic blueprint with environmental context-dependent structure and function of an organism. The dynamic proteome directly determines higher order phenotypes (complex morphology, physiology, behavior) . Thus, proteomics approaches allow studies of organisms and their tissues as integrated systems rather than a single or few molecules/ traits at a time, which facilitates network analyses and network decomposition . The combination of quantitative proteomics with functional genomics approaches permits causal linkages of genotypes to phenotypes that are adaptive in extreme and fluctuating environments.
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