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A new epipelic freshwater cyanobacterium, Komvophoron kgarii sp. nov., was identified from a perennial wallum stream on Fraser Island, northeastern Australia. Komvophoron kgariiv/as the first species in Komvophoron that was described on the basis of combined morphological, ultrastructural and phylogenetic attributes. The new taxon was distinguished by virtue of its obtuse-conical apical cells that became conically elongated and narrowed toward the ends as they matured. Additionally, trichome separation into hormogonia was preceded by preapical cells beginning to differentiate on either side of the fragmentation point before separation, a feature not previously recorded in this genus. Ultrastructural examination showed that thylakoids formed irregularly arranged blocks of lamellae in both longitudinal and cross-sections. Phylogenetic analysis revealed that the isolated material shared less than 91% 16S ribosomal RNA nucleotide sequence similarity with any other cyanobacterial sequence and formed a novel branch. [ABSTRACT FROM AUTHOR]

Black band disease (BBD) is a pathogenic microbial consortium dominated in terms of biomass by phycoerythrin-rich, gliding, filamentous cyanobacteria. Studies of BBD using molecular methods have shown that the 16S rRNA gene sequence of'Oscillatoria' sp. is consistently found in BBD samples worldwide. The purpose of this study is to erect a new genus, Roseofilum gen. et sp. nov., encompassing these and other previously reported strains. Using a polyphasic approach we characterized two strains of BBD Oscillatoria isolated from BBD infected corals in the Caribbean. These strains have the ability to tolerate sulphide, anoxia, and pH values in the range from 4.5 to 10, with optimal growth at pH 6 to 8. Growth occurs by photoautotrophy, including sulphide-insensitive oxygenic photosynthesis, and mixotrophy but not by heterotrophy under dark aerobic or anaerobic conditions. Both strains synthesize microcystin-LR. Results of infectivity experiments carried out under controlled laboratory conditions showed that both strains are capable of initiating an infection on healthy coral that resembles in situ BBD. 16S rRNA gene sequence data place these strains into a highly supported clade with other strains identified as Oscillatoria sensu lato, yet clearly genetically distinct from the type, Oscillatoria princeps. Further, while the BBD strains share more morphological similarity with members of Phormidium, they are also distinct from this genus based on sequence data. Based on morphology, ecology, physiology, and phylogenetic distinctiveness, we propose the novel epithet Roseofilum reptotaenium. [ABSTRACT FROM AUTHOR]

D adheech P.K., A bed R.M.M., M ahmoud H., K rishna M ohan M. and K rienitz L. 2012. Polyphasic characterization of cyanobacteria isolated from desert crusts, and the description of Desertifilum tharense gen. et sp. nov. (Oscillatoriales) Phycologia 51: 260-270. DOI: 10.2216/09-51.1 Four new cyanobacterial strains isolated from biological desert crusts in Thar Desert, India were characterized using a polyphasic approach. The strains were designated to two mophotypes, but all strains exhibited identical 16S ribosomal RNA (rRNA) gene sequences. On the basis of 16S rRNA phylogenetic reconstruction, the strains belonged to the Oscillatoriales order and formed a coherent cluster in the phylogenetic tree, with more than 5% sequence divergence to the closest relative belonging to a species of Microcoleus Desmazières ex Gomont. Our strains were different from the genus Microcoleus in phenotypic characters such as organization of thallus, trichome width, cell shape, gas vesicle, thylakoid arrangement and habitat. Although the strains shared some morphological similarities with members of Phormidiaceae, they differed in thylakoid pattern and 16S rRNA gene sequences. The type strain (PD2001/TDC17T) grew up to 45°C with optimum growth between 30 and 35°C. The sharp decrease in growth of that strain at 1% salinity indicates its sensitivity to salts. Phylogenetic, morphological, ultrastuctural and physiological analyses demonstrated that the investigated strains represented a novel cyanobacterial genus, for which the name Desertifilum tharense gen. et sp. nov. is proposed, with PD2001/TDC17T ( = CCAP 1420/4T = BISR/CYANO/61T) as the type strain. [ABSTRACT FROM AUTHOR]

D'A lelio D. and S almaso N. 2011. Occurrence of an uncommon (Cyanoprokaryota, Oscillatoriales) in a deep lake south of the Alps. 50: 379--383. DOI: 10.2216/10-73.1 While the widespread red filaments of are considered a typical cyanobacterium of the deep lakes of the subalpine district (Central Europe), we report a massive occurrence of unexpected specimens in Lake Idro (Northern Italy). Many strains isolated from water samples that were collected during two sampling campaigns developed filaments up to some milimetres long when placed in culture and developed clustering yellow aggregates, visible by eye in dense cultures. Among yellow strains, 40 were analysed genetically and showed unique patterns in the coding-genes rpoC1 and rbcLX. By combining morphological observations and genetic analyses, we provisionally ascribed these strains to cf. , a rare and poorly studied species, no culture of which is currently included in public algal collections. [ABSTRACT FROM AUTHOR]

Arthrospira comprises multicellular, cylindrical, usually screwlike coiled trichomes and is cultivated commercially. In this study, 33 new strains of Arthrospira isolated from plankton samples collected in Mexico, East Africa and India were investigated and compared with 53 strains or samples of earlier considerations. The study included observations of morphological features and molecular phylogenetic analyses on the basis of nucleotide sequences of internal transcribed spacer (ITS) between 16S rRNA and 23S rRNA genes and partial sequences of beta and alpha subunits including intergenic spacer (cpcBA-IGS) of phycocyanin operon. Morphological traits of Arthrospira such as trichome width, type of coiling and apical cell were not always consistent in culture conditions. It was revealed that Arthrospira phylogeny on the basis of cpcBA-IGS locus was broadly comparable with the ITS region as both phylogenetic trees derived from nucleotide sequences could be divided into two main clusters. Cluster I comprised sequences from American strains mainly, whereas cluster II contained the sequences of the strains originating from Africa and Asia chiefly. Both genetic regions of the strains investigated in the present study coincidently showed a significant sequence divergence among Arthrospira strains from East Africa, India and Mexico indicating possible distinct evolutionary lineages. [ABSTRACT FROM AUTHOR]