title: Isolation and characterization of a Mn(II)-oxidizing Bacillus strain from the demosponge Suberites domuncula.
abstract: In this study we demonstrate that the demosponge Suberites domuncula harbors a Mn(II)-oxidizing bacterium, a Bacillus strain, termed BAC-SubDo-03. Our studies showed that Mn(II) stimulates bacterial growth and induces sporulation. Moreover, we show that these bacteria immobilize manganese on their cell surface. Comparison of the 16S rDNA sequence allowed the grouping of BAC-SubDo-03 to the Mn-precipitating bacteria. Analysis of the spore cell wall revealed that it contains an Mn(II)-oxidizing enzyme. Co-incubation studies of BAC-SubDo-03 with 100 μM MnCl(2) and >1 μM of CuCl(2) showed an increase in their Mn(II)-oxidizing capacity. In order to prove that a multicopper oxidase-like enzyme(s) (MCO) exists in the cell wall of the S. domuncula-associated BAC-SubDo-03 Bacillus strain, the gene encoding this enzyme was cloned (mnxG-SubDo-03). Sequence alignment of the deduced MCO protein (MnxG-SubDo-03) revealed that the sponge bacterium clusters together with known Mn(II)-oxidizing bacteria. The expression of the mnxG-SubDo-03 gene is under strong control of extracellular Mn(II). Based on these findings, we assume that BAC-SubDo-03 might serve as a Mn reserve in the sponge providing the animal with the capacity to detoxify Mn in the environment. Applying the in vitro primmorph cell culture system we could demonstrate that sponge cells, that were co-incubated with BAC-SubDo-03 in the presence of Mn(II), show an increased proliferation potential.
authors.affiliation: National Research Center for Geoanalysis, 26 Baiwanzhuang Dajie, CHN-100037 Beijing, China. wxh0408@hotmail.com
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
authors.forename: Matthias
authors.initials: M
authors.lastname: Wiens
authors.forename: Mugdha
authors.initials: M
authors.lastname: Divekar
authors.forename: Vladislav A
authors.initials: VA
authors.lastname: Grebenjuk
authors.forename: Heinz C
authors.initials: HC
authors.lastname: Schröder
authors.forename: Renato
authors.initials: R
authors.lastname: Batel
authors.forename: Werner E G
authors.initials: WE
authors.lastname: Müller
mesh_terms: D000818:Animals; D001407:Bacillus / Q000145:classification / Q000302:isolation & purification* / Q000378:metabolism* / Q000502:physiology; D002473:Cell Wall / Q000502:physiology; D003001:Cloning, Molecular; D003300:Copper / Q000494:pharmacology; D003470:Culture Media; D015870:Gene Expression; D008345:Manganese / Q000737:chemistry / Q000378:metabolism*; D009792:Oceans and Seas; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D010957:Plasmids; D011161:Porifera; D013171:Spores, Bacterial / Q000254:growth & development; D047233:Suberites / Q000382:microbiology*
chemical_list: D003470:Culture Media; D008345:Manganese; D003300:Copper; D010088:Oxidoreductases; C024748:copper oxidase