title: De novo synthesis and functional analysis of the phosphatase-encoding gene acI-B of uncultured Actinobacteria from Lake Stechlin (NE Germany).
abstract: The National Center for Biotechnology Information [http://www.ncbi.nlm.nih.gov/guide/taxonomy/] database enlists more than 15,500 bacterial species. But this also includes a plethora of uncultured bacterial representations. Owing to their metabolism, they directly influence biogeochemical cycles, which underscores the the important status of bacteria on our planet. To study the function of a gene from an uncultured bacterium, we have undertaken a de novo gene synthesis approach. Actinobacteria of the acI-B subcluster are important but yet uncultured members of the bacterioplankton in temperate lakes of the northern hemisphere such as oligotrophic Lake Stechlin (NE Germany). This lake is relatively poor in phosphate (P) and harbors on average ~1.3 x 10 6 bacterial cells/ml, whereby Actinobacteria of the ac-I lineage can contribute to almost half of the entire bacterial community depending on seasonal variability. Single cell genome analysis of Actinobacterium SCGC AB141-P03, a member of the acI-B tribe in Lake Stechlin has revealed several phosphate-metabolizing genes. The genome of acI-B Actinobacteria indicates potential to degrade polyphosphate compound. To test for this genetic potential, we targeted the exoP-annotated gene potentially encoding polyphosphatase and synthesized it artificially to examine its biochemical role. Heterologous overexpression of the gene in Escherichia coli and protein purification revealed phosphatase activity. Comparative genome analysis suggested that homologs of this gene should be also present in other Actinobacteria of the acI lineages. This strategic retention of specialized genes in their genome provides a metabolic advantage over other members of the aquatic food web in a P-limited ecosystem. [Int Microbiol 2016; 19(1):39-47].
authors.affiliation: 1Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Stechlin, Germany.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Srivastava
authors.affiliation: Departments of Civil and Environmental Engineering, and Bacteriology, University of Wisconsin at Madison, Madison, WI, USA.
authors.forename: Katherine D
authors.initials: KD
authors.lastname: McMahon
authors.affiliation: Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, USA.
authors.forename: Ramunas
authors.initials: R
authors.lastname: Stepanauskas
authors.affiliation: Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Stechlin, Germany.|Potsdam University, Institute for Biochemistry and Biology, Potsdam, Germany.|Berlin-Brandenburg Institute of Advanced Biodiversity Research, Berlin, Germanyy.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Grossart
mesh_terms: D039903:Actinobacteria / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D017753:Ecosystem; D005858:Germany; D060106:Lakes / Q000032:analysis / Q000382:microbiology*; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics* / Q000378:metabolism*; D010802:Phylogeny
chemical_list: D001426:Bacterial Proteins; D010744:Phosphoric Monoester Hydrolases
keywords: Lake Stechlin, NE Germany; acI-B in Actinobacteria; phosphatases; phosphate limitation; single cell genomics