title: Candidatus "Thiodictyon syntrophicum", sp. nov., a new purple sulfur bacterium isolated from the chemocline of Lake Cadagno forming aggregates and specific associations with Desulfocapsa sp.
abstract: Strain Cad16(T) is a small-celled purple sulfur bacterium (PSB) isolated from the chemocline of crenogenic meromictic Lake Cadagno, Switzerland. Long term in situ observations showed that Cad16(T) regularly grows in very compact clumps of cells in association with bacteria belonging to the genus Desulfocapsa in a cell-to-cell three dimensional structure. Previously assigned to the genus Lamprocystis, Cad16(T), was here reclassified and assigned to the genus Thiodictyon. Based on comparative 16S rRNA gene sequences analysis, isolate Cad16(T) was closely related to Thiodictyon bacillosum DSM234(T) and Thiodictyon elegans DSM232(T) with sequence similarities of 99.2% and 98.9%, respectively. Moreover, matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) analysis separated Cad16(T) from other PSB genera, Lamprocystis and Thiocystis. Major differences in cell morphology (oval-sphere compared to rod-shaped) and arrangement (no netlike cell aggregates), carotenoid group (presence of okenone instead of rhodopinal), chemolithotrophic growth as well as the ability to form syntrophic associations with a sulfate-reducing bacteria of the genus Desulfocapsa suggested a different species within the genus Thiodictyon. This isolate is therefore proposed and described as Candidatus "Thiodictyon syntrophicum" sp. nov., a provisionally novel species within the genus Thiodictyon.
authors.affiliation: Alpine Biology Centre Foundation, Piora, Quinto, Switzerland.
authors.forename: Sandro
authors.initials: S
authors.lastname: Peduzzi
authors.forename: Nicola
authors.initials: N
authors.lastname: Storelli
authors.forename: Allana
authors.initials: A
authors.lastname: Welsh
authors.forename: Raffaele
authors.initials: R
authors.lastname: Peduzzi
authors.forename: Dittmar
authors.initials: D
authors.lastname: Hahn
authors.forename: Xavier
authors.initials: X
authors.lastname: Perret
authors.forename: Mauro
authors.initials: M
authors.lastname: Tonolla
mesh_terms: D001422:Bacterial Adhesion; D018407:Bacterial Physiological Phenomena; D015373:Bacterial Typing Techniques; D002841:Chromatiaceae / Q000737:chemistry / Q000145:classification* / Q000302:isolation & purification* / Q000502:physiology; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D020564:Deltaproteobacteria / Q000502:physiology*; D005618:Fresh Water / Q000382:microbiology*; D008853:Microscopy; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013557:Switzerland
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S