Identification and analysis of two sequences encoding ice-binding proteins obtained from a putative bacterial symbiont of the psychrophilic Antarctic ciliate Euplotes focardii

2014 ◽  
Vol 26 (5) ◽  
pp. 491-501 ◽  
Author(s):  
Sandra Pucciarelli ◽  
Federica Chiappori ◽  
Raghul Rajan Devaraj ◽  
Guang Yang ◽  
Ting Yu ◽  
...  
Keyword(s):  
Amino Acid Level ◽  
Bacterial Symbiont ◽  
The Arctic ◽  
Glacial Ice ◽  
Mould Fungus ◽  
Lake Vostok ◽  
Ice Binding ◽  
Stigmatella Aurantiaca ◽  
Ice Binding Protein ◽  
The Antarctic

AbstractWe identified two ice-binding protein (IBP) sequences, named EFsymbAFP and EFsymbIBP, from a putative bacterial symbiont of the Antarctic psychrophilic ciliate Euplotes focardii. EFsymbAFP is 57.43% identical to the antifreeze protein (AFP) from the Stigmatella aurantiaca strain DW4/3-1, which was isolated from the Victoria Valley lower glacier. EFsymbIBP is 53.38% identical to the IBP from the Flavobacteriaceae bacterium strain 3519-10, isolated from the glacial ice of Lake Vostok. EFsymbAFP and EFsymbIBP are 31.73% identical at the amino acid level and are organized in tandem on the bacterial chromosome. The relatively low sequence identity and the tandem organization, which appears unique to this symbiont, suggest an occurrence of horizontal gene transfer (HGT). Structurally, EFsymbAFP and EFsymbIBP are similar to the AFPs from the snow mould fungus Typhula ishikariensis and from the Arctic yeast Leucosporidium sp. AY30. A phylogenetic analysis showed that EFsymbAFP and EFsymbIBP cluster principally with the IBP sequences from other Antarctic bacteria, supporting the view that these sequences belong to an Antarctic symbiontic bacterium of E. focardii. These results confirm that IBPs have a complex evolutionary history, which includes HGT events, most probably due to the demands of the environment and the need for rapid adaptation.

Cryopreservative Effects of the Recombinant Ice-Binding Protein from the Arctic Yeast Leucosporidium sp. on Red Blood Cells

2012 ◽  
Vol 167 (4) ◽  
pp. 824-834 ◽  
Author(s):  
Sung Gu Lee ◽  
Hye Yeon Koh ◽  
Jun Hyuck Lee ◽  
Sung-Ho Kang ◽  
Hak Jun Kim
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Binding Protein ◽  
The Arctic ◽  
Ice Binding ◽  
Ice Binding Protein

Structure-based characterization and antifreeze properties of a hyperactive ice-binding protein from the Antarctic bacteriumFlavobacterium frigorisPS1

2014 ◽  
Vol 70 (4) ◽  
pp. 1061-1073 ◽  
Author(s):  
Hackwon Do ◽  
Soon-Jong Kim ◽  
Hak Jun Kim ◽  
Jun Hyuck Lee
Keyword(s):  
Amino Acid ◽  
Binding Site ◽  
Disulfide Bond ◽  
Binding Protein ◽  
Size Exclusion ◽  
Sequence Alignments ◽  
Ice Binding ◽  
Ice Binding Protein ◽  
Binding Residues ◽  
The Antarctic

Ice-binding proteins (IBPs) inhibit ice growth through direct interaction with ice crystals to permit the survival of polar organisms in extremely cold environments. FfIBP is an ice-binding protein encoded by the Antarctic bacteriumFlavobacterium frigorisPS1. The X-ray crystal structure of FfIBP was determined to 2.1 Å resolution to gain insight into its ice-binding mechanism. The refined structure of FfIBP shows an intramolecular disulfide bond, and analytical ultracentrifugation and analytical size-exclusion chromatography show that it behaves as a monomer in solution. Sequence alignments and structural comparisons of IBPs allowed two groups of IBPs to be defined, depending on sequence differences between the α2 and α4 loop regions and the presence of the disulfide bond. Although FfIBP closely resemblesLeucosporidium(recently re-classified asGlaciozyma) IBP (LeIBP) in its amino-acid sequence, the thermal hysteresis (TH) activity of FfIBP appears to be tenfold higher than that of LeIBP. A comparison of the FfIBP and LeIBP structures reveals that FfIBP has different ice-binding residues as well as a greater surface area in the ice-binding site. Notably, the ice-binding site of FfIBP is composed of a T-A/G-X-T/N motif, which is similar to the ice-binding residues of hyperactive antifreeze proteins. Thus, it is proposed that the difference in TH activity between FfIBP and LeIBP may arise from the amino-acid composition of the ice-binding site, which correlates with differences in affinity and surface complementarity to the ice crystal. In conclusion, this study provides a molecular basis for understanding the antifreeze mechanism of FfIBP and provides new insights into the reasons for the higher TH activity of FfIBP compared with LeIBP.

scholarly journals Fungi in the Antarctic Cryosphere: Using DNA Metabarcoding to Reveal Fungal Diversity in Glacial Ice from the Antarctic Peninsula Region

2021 ◽  
Author(s):  
Graciéle Cunha Alves de Menezes ◽  
Paulo E. A. S. Câmara ◽  
Otávio Henrique Bezerra Pinto ◽  
Peter Convey ◽  
Micheline Carvalho-Silva ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Fungal Diversity ◽  
Glacial Ice ◽  
Dna Metabarcoding ◽  
The Antarctic

scholarly journals Whole-genome sequencing of the endemic Antarctic fungus Antarctomyces pellizariae reveals an ice-binding protein, a scarce set of secondary metabolites gene clusters and provides insights on Thelebolales phylogeny

Genomics ◽  
2020 ◽  
Vol 112 (5) ◽  
pp. 2915-2921 ◽  
Author(s):  
Thiago Mafra Batista ◽  
Heron Oliveira Hilario ◽  
Gabriel Antônio Mendes de Brito ◽  
Rennan Garcias Moreira ◽  
Carolina Furtado ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Binding Protein ◽  
Protein A ◽  
Gene Clusters ◽  
Whole Genome ◽  
Ice Binding ◽  
Ice Binding Protein

scholarly journals Neutrino Astronomy with IceCube

2016 ◽  
Vol 12 (S324) ◽  
pp. 322-329
Author(s):  
Kevin J. Meagher
Keyword(s):  
Real Time ◽  
Gamma Ray ◽  
Galactic Plane ◽  
Galactic Nuclei ◽  
High Energy ◽  
Glacial Ice ◽  
Astrophysical Neutrinos ◽  
Charged Secondary ◽  
Neutrino Astronomy ◽  
The Antarctic

AbstractThe IceCube Neutrino Observatory is a cubic kilometer neutrino telescope located at the Geographic South Pole. Cherenkov radiation emitted by charged secondary particles from neutrino interactions is observed by IceCube using an array of 5160 photomultiplier tubes embedded between a depth of 1.5 km to 2.5 km in the Antarctic glacial ice. The detection of astrophysical neutrinos is a primary goal of IceCube and has now been realized with the discovery of a diffuse, high-energy flux consisting of neutrino events from tens of TeV up to several PeV. Many analyses have been performed to identify the source of these neutrinos: correlations with active galactic nuclei, gamma-ray bursts, and the galactic plane. IceCube also conducts multi-messenger campaigns to alert other observatories of possible neutrino transients in real-time. However, the source of these neutrinos remains elusive as no corresponding electromagnetic counterparts have been identified. This proceeding will give an overview of the detection principles of IceCube, the properties of the observed astrophysical neutrinos, the search for corresponding sources (including real-time searches), and plans for a next-generation neutrino detector, IceCube–Gen2.

scholarly journals Metagenomic Analysis of Stress Genes in Microbial Mat Communities from Antarctica and the High Arctic

2011 ◽  
Vol 78 (2) ◽  
pp. 549-559 ◽  
Author(s):  
Thibault Varin ◽  
Connie Lovejoy ◽  
Anne D. Jungblut ◽  
Warwick F. Vincent ◽  
Jacques Corbeil
Keyword(s):  
High Arctic ◽  
Environmental Stresses ◽  
The Arctic ◽  
Functional Responses ◽  
Protein Coding ◽  
Content Type ◽  
Stress Genes ◽  
Cyanobacterial Genes ◽  
Shock Proteins ◽  
The Antarctic

ABSTRACTPolar and alpine microbial communities experience a variety of environmental stresses, including perennial cold and freezing; however, knowledge of genomic responses to such conditions is still rudimentary. We analyzed the metagenomes of cyanobacterial mats from Arctic and Antarctic ice shelves, using high-throughput pyrosequencing to test the hypotheses that consortia from these extreme polar habitats were similar in terms of major phyla and subphyla and consequently in their potential responses to environmental stresses. Statistical comparisons of the protein-coding genes showed similarities between the mats from the two poles, with the majority of genes derived fromProteobacteriaandCyanobacteria; however, the relative proportions differed, with cyanobacterial genes more prevalent in the Antarctic mat metagenome. Other differences included a higher representation ofActinobacteriaandAlphaproteobacteriain the Arctic metagenomes, which may reflect the greater access to diasporas from both adjacent ice-free lands and the open ocean. Genes coding for functional responses to environmental stress (exopolysaccharides, cold shock proteins, and membrane modifications) were found in all of the metagenomes. However, in keeping with the greater exposure of the Arctic to long-range pollutants, sequences assigned to copper homeostasis genes were statistically (30%) more abundant in the Arctic samples. In contrast, more reads matching the sigma B genes were identified in the Antarctic mat, likely reflecting the more severe osmotic stress during freeze-up of the Antarctic ponds. This study underscores the presence of diverse mechanisms of adaptation to cold and other stresses in polar mats, consistent with the proportional representation of major bacterial groups.

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