title: Exploring the Antarctic soil metagenome as a source of novel cold-adapted enzymes and genetic mobile elements.
abstract: Metagenomic library PP1 was obtained from Antarctic soil samples. Both functional and genotypic metagenomic screening were used for the isolation of novel cold-adapted enzymes with potential applications, and for the detection of genetic elements associated with gene mobilization, respectively. Fourteen lipase/esterase-, 14 amylase-, 3 protease-, and 11 cellulase-producing clones were detected by activity-driven screening, with apparent maximum activities around 35 °C for both amylolytic and lipolytic enzymes, and 35-55 °C for cellulases, as observed for other cold-adapted enzymes. However, the behavior of at least one of the studied cellulases is more compatible to that observed for mesophilic enzymes. These enzymes are usually still active at temperatures above 60 °C, probably resulting in a psychrotolerant behavior in Antarctic soils. Metagenomics allows to access novel genes encoding for enzymatic and biophysic properties from almost every environment with potential benefits for biotechnological and industrial applications. Only intI- and tnp-like genes were detected by PCR, encoding for proteins with 58-86 %, and 58-73 % amino acid identity with known entries, respectively. Two clones, BAC 27A-9 and BAC 14A-5, seem to present unique syntenic organizations, suggesting the occurrence of gene rearrangements that were probably due to evolutionary divergences within the genus or facilitated by the association with transposable elements. The evidence for genetic elements related to recruitment and mobilization of genes (transposons/integrons) in an extreme environment like Antarctica reinforces the hypothesis of the origin of some of the genes disseminated by mobile elements among "human-associated" microorganisms.
authors: Laboratoire de Macromolécules Biologiques, Centre d'Ingénierie des Protéines, Université de Liège, Belgium.
authors: Renaud
authors: R
authors: Berlemont
authors: Delphine
authors: D
authors: Pipers
authors: Maud
authors: M
authors: Delsaute
authors: Federico
authors: F
authors: Angiono
authors: Georges
authors: G
authors: Feller
authors: Moreno
authors: M
authors: Galleni
authors: Pablo
authors: P
authors: Power
mesh_terms: D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D000864:Antarctic Regions; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D003001:Cloning, Molecular; D003081:Cold Climate; D004798:Enzymes / Q000235:genetics* / Q000302:isolation & purification; D005308:Fertilizers; D005742:Gasoline; D015723:Gene Library; D020071:Interspersed Repetitive Sequences / Q000235:genetics*; D054892:Metagenome; D008969:Molecular Sequence Data; D010578:Petroleum; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012988:Soil Microbiology; D012989:Soil Pollutants
chemical_list: D004798:Enzymes; D005308:Fertilizers; D005742:Gasoline; D010578:Petroleum; D012989:Soil Pollutants