title: Comparison of the compatible solute pool of two slightly halophilic planctomycetes species, Gimesia maris and Rubinisphaera brasiliensis.
abstract: Gimesia maris and Rubinisphaera brasiliensis are slightly halophilic representatives of the deep-branching phylum Planctomycetes. For osmoadaptation both species accumulated α-glutamate, sucrose, ectoine and hydroxyectoine. A major role was found for ectoine, hydroxyectoine as well as sucrose under hyper-osmotic shock conditions. Nevertheless, the levels of sucrose were up-regulated by the increased salinity levels and also by low nitrogen availability. Additionally, G. maris accumulated glucosylglycerate (GG) as major solute specifically under low nitrogen levels, which prompted us to analyse the transcript abundance of two homologues genes known for the biosynthesis of GG, namely glucosyl-3-phosphoglycerate synthase (GpgS) and glucosyl-3-phosphoglycerate phosphatase (GpgP). By qPCR using a suitable reference gene selected in this study, the transcript abundance of the biosynthetic genes was quantified in G. maris cells under hyper-osmotic shock or under low nitrogen conditions. The gpgS gene was induced under nitrogen-limiting conditions suggesting that GG synthesis is regulated primarily at the transcription level. Moreover, the expression of a gene coding for a putative sucrose-phosphorylase (Spase) located upstream the gpgS and gpgP genes was up-regulated, predicting a metabolic role of Spase probably related to GG synthesis.
authors: Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal.
authors: Catarina
authors: C
authors: Ferreira
authors: Department of Medical Sciences and Institute for Biomedicine-iBiMED, University of Aveiro, 3810-193, Aveiro, Portugal.
authors: Ana R
authors: AR
authors: Soares
authors: Centro de Ressonância Magnética António Xavier, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2781-901, Oeiras, Portugal.
authors: Pedro
authors: P
authors: Lamosa
authors: Department of Medical Sciences and Institute for Biomedicine-iBiMED, University of Aveiro, 3810-193, Aveiro, Portugal.
authors: Manuel A
authors: MA
authors: Santos
authors: Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504, Coimbra, Portugal. milton@ci.uc.pt.
authors: Milton S
authors: MS
authors: da Costa
mesh_terms: D001419:Bacteria / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D005960:Glucosides / Q000378:metabolism*; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D005988:Glyceric Acids / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D009997:Osmotic Pressure; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D010933:Plankton / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D055049:Salt Tolerance
chemical_list: C509251:2-glucosylglycerate; D001426:Bacterial Proteins; D005960:Glucosides; D005988:Glyceric Acids; D005964:Glucosyltransferases; D010744:Phosphoric Monoester Hydrolases; D009584:Nitrogen
keywords: Compatible solutes; Gimesia maris; Planctomycetes; Rubinisphaera brasiliensis; qPCR