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Free-Living Ice-Nucleating Active Bacteria from High Mountain Lake Habitats

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Author(s): MUNTI YUHANA | KURT HANSELMANN

Journal: Microbiology Indonesia
ISSN 1978-3477

Volume: 2;
Issue: 3;
Start page: 131;
Date: 2008;
Original page

Keywords: high mountain lake habitats | ice nucleation | 16S rRNA gene | free-living bacteria

ABSTRACT
We collected the culturable heterotrophic bacteria from oligotrophic high mountain lake habitats and tested their capability to induce ice formation. Direct plating was carried out using low-nutrient medium at a temperature of between 3 and 4°C. As many as 84 isolates were recovered from glacial ice and natural biofilm growing on granite rocks surface. Six out of 84 isolates were capable of expressing the ice-nucleation phenotype. After autoclaving the cell suspension at 121°C for 15 min, isolate J78 was still able to retain the ability for ice formation. Heat-stable ice nuclei produced by ice-nucleating active bacteria have potential applications in biotechnology. Characterization of INA bacteria was performed employing live-dead Gram staining and molecular methods. Universal primers for Bacteria (S-D-Bact-0008-b-S-20 and S-D-Bact-1524-a-A-18) were used for PCR to amplify almost the full length of the 16S rRNA genes of selected INA isolates. Restriction fragment length polymorphism analysis resulted in 2 unique patterns, as represented by J43 and J83, respectively. Based on DNA sequencing of 16S rRNA gene, isolate J43 (GeneBank accession no. AJ864852) was closely related to Pseudomonas mephitica (99.2% sequence similarity) and Janthinobacterium lividum (99% similarity), whereas isolate J83 (GeneBank accession no. AJ864859) showed 100% sequence identity to Pseudomonas fluorescens.
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