@article {4634, title = {Draft genome sequence of the Antarctic green alga Chlamydomonas sp. UWO241}, journal = {iScience}, volume = {24}, year = {2021}, month = {2021-02}, pages = {102084}, abstract = {

Antarctica is home to an assortment of psychrophilic algae, which have evolved various survival strategies for coping with their frigid environments. Here, we explore Antarctic psychrophily by examining the \∼212 Mb draft nuclear genome of the green alga Chlamydomonas\ sp. UWO241, which resides within the water column of a perennially ice-covered, hypersaline lake. Like certain other Antarctic algae, UWO241 encodes a large number (\≥37) of ice-binding proteins, putatively originating from horizontal gene transfer. Even more striking, UWO241 harbors hundreds of highly similar duplicated genes involved in diverse cellular processes, some of which we argue are aiding its survival in the Antarctic via gene dosage. Gene and partial gene duplication appear to be an ongoing phenomenon within UWO241, one which might be mediated by retrotransposons. Ultimately, we consider how such a process could be associated with adaptation to extreme environments but explore potential non-adaptive hypotheses as well.

}, keywords = {LTER-MCM}, issn = {25890042}, doi = {10.1016/j.isci.2021.102084}, url = {https://www.sciencedirect.com/science/article/pii/S2589004221000523}, author = {Zhang, Xi and Cvetkovska, Marina and Rachael M. Morgan-Kiss and H{\"u}ner, Norman P. A. and Smith, David Roy} } @article {4152, title = {Drivers of protistan community autotrophy and heterotrophy in chemically stratified Antarctic lakes}, journal = {Aquatic Microbial Ecology}, volume = {82}, year = {2019}, month = {01/2019}, pages = {225 - 239}, abstract = {

Single-celled, eukaryotic microorganisms, known as protists, are responsible for 2 important, yet opposing, metabolic activities within aquatic food webs. They are major primary producers and highly active predators in marine and fresh water systems. While genomics has accelerated in recent years for this taxonomically diverse group, our understanding of the metabolic capabilities of most protists remains limited. It is also poorly understood how protist trophic mode is affected by biotic and abiotic factors, and therefore it is difficult to predict how events such as global climate change will affect the balance between autotrophic and heterotrophic activities in protist communities. To address open questions regarding how protist metabolic versatility is influenced by their environment, we characterized the potential for carbon fixation versus organic carbon degradation using enzymatic assays (RubisCO and β-D-glucosaminidase, respectively) within the water columns of ice-covered lakes in McMurdo Dry Valleys (MDV), Antarctica. Steep physical and chemical gradients in the water columns, microorganism domination and minimal allochthonous inputs makes the MDV lakes uniquely suited to investigate environment-microbe interactions. Spatial trends in RubisCO and β-D-glucosaminidase activities were lake-specific and vertically stratified within the water columns. Moreover, bottom-up drivers controlling the activity of C-fixation vs. organic C-degradation among the MDV protist communities were distinct between the upper photic vs. the deep, aphotic zones. We conclude that differential controls over major C-cycling enzymes have important implications on the influence of environmental change on the carbon and nutrient cycles in the MDV lakes.

}, keywords = {LTER-MCM, Antarctic lakes, Aquatic protists, Autotrophy, Heterotrophy, McMurdo Dry Valleys, RubisCO, β-D-glucosaminidase}, issn = {0948-3055}, doi = {10.3354/ame01891}, url = {https://www.int-res.com/abstracts/ame/v82/n3/p225-239/}, author = {Li, Wei and Dolhi-Binder, J and Cariani, ZE and Rachael M. Morgan-Kiss} } @article {1118, title = {Diversity and Expression of RubisCO Genes in a Perennially Ice-Covered Antarctic Lake during the Polar Night Transition}, journal = {Applied and Environmental Microbiology}, volume = {78}, year = {2012}, month = {04/2012}, pages = {4358-4366}, keywords = {LTER-MCM}, url = {http://aem.asm.org/content/78/12/4358.short}, author = {Weidong Kong and David C. Ream and John C. Priscu and Rachael M. Morgan-Kiss} }