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Antarctic population of Anteholosticha sigmoidea (Foissner, 1982) Berger, 2003 (Ciliophora: Urostylidae) with notes on its phylogenetic position

2022-04-14T07:18:37Z

Title: Antarctic population of Anteholosticha sigmoidea (Foissner, 1982) Berger, 2003 (Ciliophora: Urostylidae) with notes on its phylogenetic position Authors: Kim, Kang-San; Ji, Su-Jung; Kim, Sanghee; Min, Gi-Sik Abstract: Anteholosticha sigmoidea (Foissner, 1982) Berger, 2003 was isolated from a wet soil sample collected on King George Island, Antarctica. Morphological observations and molecular phylogenetic analyses based on the gene sequences of small subunit ribosomal RNA (18S rRNA) were used to identify the species. Anteholosticha sigmoidea can be divided into two groups: group I (three populations described by Foissner 1982) and group II (described by Foissner 1984) based on the morphological differences. Group I differs from group II by the length of the midventral complex (65.1% vs. 52.5% of the cell length), the number of adoral membranelles (25?28 vs. 16?24), and the number of dorsal bristles in kinety 1 (16 bristles vs. nine bristles). Group I differs from the Antarctica population by the absence/presence of the collecting canals of the contractile vacuole and the number of macronuclear nodules (6?12 vs. 13?19). Group II differs from the Antarctica population by the number of macronuclear nodules (five to nine vs. 13?19); the arrangement of cortical granules (forming longitudinal rows vs. irregularly distributed); the length of the midventral complex (64.7% vs. 53.8% of cell length). In the phylogenetic analyses, A. sigmoidea was not nested with any species, and the gene tree indicated polyphyly of the genus Anteholosticha.

Modeling Responses of Terrestrial Organisms to Environmental Changes on King George Island

2022-03-24T07:14:36Z

Title: Modeling Responses of Terrestrial Organisms to Environmental Changes on King George Island Authors: Lee, Hyoungseok

Microbiome in Cladonia squamosa Is Vertically Stratified According to Microclimatic Conditions

2022-03-24T07:14:15Z

Title: Microbiome in Cladonia squamosa Is Vertically Stratified According to Microclimatic Conditions Authors: Noh, Hyun-Ju; Lee, Yung Mi; Park, Chae Haeng; Lee, Hong Kum; Cho, Jang-Cheon; Hong, Soon Gyu Abstract: Lichens are miniature ecosystems that contain fungi, microalgae, and bacteria. It is generally accepted that symbiosis between mycobiont and photobiont and microbial contribution to the ecosystem support the wide distribution of lichens in terrestrial ecosystems, including polar areas. The composition of symbiotic components can be affected by subtle microenvironmental differences within a thallus, as well as large-scale climate differences. In this study, we investigated fine-scale profiles of algal, fungal, and bacterial compositions through horizontal and vertical positions of the Antarctic lichen Cladonia squamosa colonies by next-generation sequencing of the nuclear large subunit rRNA gene (nucLSU) of eukaryotes and the 16S rRNA gene of bacteria. Apical parts of thalli were exposed to strong light, low moisture, and high variability of temperature compared with basal parts. Microbial diversity increased from apical parts to basal parts of thalli. Asterochloris erici was the major photobiont in apical positions of thalli, but other microalgal operational taxonomic units (OTUs) of Trebouxiophyceae and Ulvophyceae were major microalgal components in basal positions. Photochemical responses of algal components from apical and basal parts of thalli were quite different under variable temperature and humidity conditions. Several fungal OTUs that belonged to Arthoniomycetes and Lecanoromycetes, and diverse bacterial OTUs that belonged to Alphaproteobacteria, Acidobacteria_Gp1, and candidate division WPS-2 showed a clear distribution pattern according to their vertical positions within thalli. The overall lichen microbiome was significantly differentiated by the vertical position within a thallus. These results imply that different microclimate are formed at different lichen thallus parts, which can affect microbial compositions and physiological responses according to positions within the thalli.

Lichenihabitans psoromatis gen. nov., sp. nov., a member of a novel lineage (Lichenihabitantaceae fam. nov.) within the order of Rhizobiales isolated from Antarctic lichen

2022-03-24T07:14:33Z

Title: Lichenihabitans psoromatis gen. nov., sp. nov., a member of a novel lineage (Lichenihabitantaceae fam. nov.) within the order of Rhizobiales isolated from Antarctic lichen Authors: Noh, Hyun-Ju; Baek, Kiwoon; Hwang, Chung Yeon; Shin, Seung Chul; Hong, Soon Gyu; Lee, Yung Mi Abstract: Two Gram-stain-negative, facultative anaerobic chemoheterotrophic, pink-coloured, rod-shaped and non-motile bacterial strains, PAMC 29128 and PAMC 29148(T), were isolated from lichen. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strains PAMC 29128 and PAMC 29148(T) belong to lichen-associated Rhizobiales-1 (LAR1), an uncultured phylogenetic lineage of the order Rhizobiales and the most closely related genera were Methylocapsa (<93.9 %) and Methylosinus (<93.8 %). The results of phylogenomic and genomic relatedness analyses also showed that strains PAMC 29128 and PAMC 29148(T) were clearly distinguished from other species in the order Rhizobiales with average nucleotide identity values of <71.4% and genome-to-genome distance values of <22.7 %. Genomic analysis revealed that strains PAMC 29128 and PAMC 29148(T) did not contain genes involved in atmospheric nitrogen fixation or utilization of carbon compounds such as methane and methanol. Strains PAMC 29128 and PAMC 29148(T) were able to utilize certain monosaccharides, disaccharides, sugar alcohols and other organic compounds as a sole carbon source. The major fatty acids (>10%) were summed feature 8 (C-18:1 omega 7c and/or C-18:1 omega 6c; 33.7-39.7 %), summed feature 3 (C-16:1 omega 7c and/or C-16(:1) omega 6c; 25.2-254%) and C-19:0 cyclo omega 8c (11.9-15.4%). The major respiratory quinone was Q-10. The genomic DNA G+C contents of PAMC 29128 and PAMC 29148(T) were 63.0 and 63.1 mol%, respectively. Their distinct phylogenetic position and some physiological characteristics support the proposal of Lichenihabitans gen. nov., with the type species Lichenihabitans psoromatis sp. nov. (type strain, PAMC 29148(T)=KCCM 43293(T)=JCM 33311(T)). Lichenihabitantaceae fam. nov. is also proposed.