title: Isolation and characterization of novel cellulase genes from uncultured microorganisms in different environmental niches.
abstract: Four different environmental DNA libraries were prepared from microbial consortium collected from forest soil, dung of elephant, cow rumen and rotted tree. Seven independent clones specifying cellulase activities (five endo-beta-1,4-glucanases and two beta-glucosidases) were isolated and identified. Sequence analysis of the retrieved genes revealed that the encoded products of these cellulase genes shared less than 50% identities and 70% similarities to cellulases in the databases. Domain analysis predicted that four endo-beta-1,4-glucanases conform to glycolsyl hydrolase family 5 (GHF 5) and one endo-beta-1,4-glucanase to glycolsyl hydrolase family 9 (GHF 9), while both beta-glucosidases belong to glycolsyl hydrolase family 3 (GHF 3). Further sequence analysis indicated that although a solid affiliation could be made for the two endo-beta-1,4-glucanases to the typical ruminal microbe Prevotella ruminicola, the rest formed deep-branched lineages with no close relatives. The revelation of the phylogenetic novelty provided a snapshot on the great diversity of cellulases in these natural environments.
authors.affiliation: The State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan 250100, Shandong, China.
authors.forename: Fengchao
authors.initials: F
authors.lastname: Wang
authors.forename: Fan
authors.initials: F
authors.lastname: Li
authors.forename: Guanjun
authors.initials: G
authors.lastname: Chen
authors.forename: Weifeng
authors.initials: W
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002417:Cattle; D002480:Cellulase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004606:Elephants; D004783:Environmental Microbiology; D005243:Feces / Q000382:microbiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D012417:Rumen / Q000382:microbiology; D016415:Sequence Alignment; D012988:Soil Microbiology; D014197:Trees / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D002480:Cellulase