Antarctic Regions
Mostrando 13-17 de 17 artigos, teses e dissertações.
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13. Hot spots in cold adaptation: Localized increases in conformational flexibility in lactate dehydrogenase A4 orthologs of Antarctic notothenioid fishes
To elucidate mechanisms of enzymatic adaptation to extreme cold, we determined kinetic properties, thermal stabilities, and deduced amino acid sequences of lactate dehydrogenase A4 (A4-LDH) from nine Antarctic (−1.86 to 1°C) and three South American (4 to 10°C) notothenioid teleosts. Higher Michaelis–Menten constants (Km) and catalytic rate constants (
The National Academy of Sciences.
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14. Manganese Reduction by Microbes from Oxic Regions of the Lake Vanda (Antarctica) Water Column
Depth profiles of metals in Lake Vanda, a permanently ice-covered, stratified Antarctic lake, suggest the importance of particulate manganese oxides in the scavenging, transport, and release of metals. Since manganese oxides can be solubilized by manganese-reducing bacteria, microbially mediated manganese reduction was investigated in Lake Vanda. Microbes co
American Society for Microbiology.
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15. Bacterioplankton Secondary Production Estimates for Coastal Waters of British Columbia, Antarctica, and California
The principal objective of this study was to quantify the rate of heterotrophic bacterioplankton production. Production was estimated by two approaches: (i) measurement of increasing bacterial abundance with time in filtered (3-μm pore size) seawater and (ii) estimation of bacterial deoxyribonucleic acid synthesis by tritiated thymidine incorporation in unf
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16. Ozone depletion and UVB radiation: Impact on plant DNA damage in southern South America
The primary motivation behind the considerable effort in studying stratospheric ozone depletion is the potential for biological consequences of increased solar UVB (280–315 nm) radiation. Yet, direct links between ozone depletion and biological impacts have been established only for organisms of Antarctic waters under the influence of the ozone “hole;”
The National Academy of Sciences.
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17. A Few Cosmopolitan Phylotypes Dominate Planktonic Archaeal Assemblages in Widely Different Oceanic Provinces
We compared the phylogenetic compositions of marine planktonic archaeal populations in different marine provinces. Samples from eight different environments were collected at two depths (surface and aphotic zone), and 16 genetic libraries of PCR-amplified archaeal 16S rRNA genes were constructed. The libraries were analyzed by using a three-step hierarchical
American Society for Microbiology.