The "Nostocoida limicola" story: resolving the phylogeny of this morphotype responsible for bulking in activated sludge.

On the basis of 16S rRNA sequence analyses of several isolates of "Nostocoida limicola" from activated sludge plants in Australia and other countries, it is clear that "N. limicola" I, II and III are not three morphological variants of a single bacterium but at least three phylogenetically different bacteria. Data show that "N. limicola" I are members of at least two genera in the low mol% G+C gram-positive bacteria, while some isolates of "N. limicola" II belong to the high mol% G+C gram positive bacteria, and "N. limicola" III is a member of the Planctomycetales. Design and application of 16S rRNA targeted probes for each to biomass samples suggests that their phylogeny is more diverse than pure culture studies would suggest.

Seviour RJ ，Liu JR ，Seviour EM ，McKenzie CA ，Blackall LL ，Saint CP ... -  《WATER SCIENCE AND TECHNOLOGY》

The filamentous bacterial morphotype 'Nostocoida limicola' I contains at least two previously described genera in the low G+C gram positive bacteria.

Isolates of eight bacterial filaments fitting the published morphological description of 'Nostocoida limicola' I were obtained from the mixed liquor of four different Australian and one Czech Republic activated sludge plants by micromanipulation. On the basis of their near complete (Ben 200 and Ben 201), or partial (Ben 77, Ben 78, Ben 202, Ben 203, Ben 204 and Ben 205) 16S rRNA gene sequences, six of these isolates were 99.3-100% similar to Lactosphaera pasteurii and Trichococcus flocculiformis, a bulking filament only reported previously in Germany. The other two (Ben 203 and Ben 204) were 99.9% similar to Streptococcus suis. Hence, all are in the low mol % G+C gram-positive bacteria division of the Bacteria. On this evidence 'N. limicola' I is phylogenetically unrelated to 'Nostocoida limicola' II, which is now known to be in the Actinobacteria, even though these two filamentous bacteria appearing in activated sludge systems have been considered to be closely related to each other historically.

Liu JR ，Burrell P ，Seviour EM ，Soddell JA ，Blackall LL ，Seviour RJ ... -  《SYSTEMATIC AND APPLIED MICROBIOLOGY》

Candidatus Monilibacter spp., common bulking filaments in activated sludge, are members of Cluster III Defluviicoccus.

Two alphaproteobacterial Neisser negative 'Nostocoida limicola' morphotypes differing slightly in their trichome diameter and filament regularity were dominant populations in the Bendigo, Victoria, Australia activated sludge community removing phosphorus (P). Neither responded to the FISH probes available for any of the other alphaproteobacterial 'N. limicola' morphotypes. Instead both fluoresced with the DF988 FISH probe designed originally to target alphaproteobacterial cluster II Defluviicoccus tetrad forming organisms. A 16S rRNA based clone library from this biomass revealed that the alphaproteobacterial clones grouped closely with Candidatus 'Monilibacter batavus' and Defluviicoccus clones in a cluster separate from the existing cluster I and II Defluviicoccus. When a FISH probe was designed against these, it only hybridized to the thinner and less abundant 'N. limicola' morphotype. Micromanipulation-RT-PCR was used to selectively recover the main 'N. limicola' morphotype and a FISH probe designed against the 16S rRNA clones generated from it showed only this filament fluoresced. From FISH based surveys, both 'N. limicola' variants occurred frequently in phosphorus removal activated sludge systems in Australia treating domestic waste. The data suggest that they represent two new strains of Candidatus 'Monilibacter', which on this evidence are filamentous members of the genus Defluviicoccus, a potential competitor for the polyphosphate accumulating organisms in these communities.

Nittami T ，McIlroy S ，Seviour EM ，Schroeder S ，Seviour RJ ... -  《-》

Phylogeny of the filamentous bacterium 'Nostocoida limicola' III from activated sludge.

:Five strains of the filamentous bacterium 'Nostocoida limicola' III were successfully isolated into pure culture from samples of activated sludge biomass from five plants in Australia. 16S rRNA gene sequence analyses showed that all isolates were members of the Planctomycetales, most closely related to Isosphaera pallida, but they differed phenotypically from this species in that they did not glide and were not thermotolerant. The ultrastructure of these 'N. limicola' III isolates was also consistent with them being Planctomycetales, in that they possessed complex intracellular membrane systems compartmentalizing the cells. However, the arrangements of these intracellular membranes differed between isolates. These data confirm that 'N. limicola' III is phylogenetically unrelated to both 'N. limicola' I and 'N. limicola' II, activated sludge filamentous bacteria which share morphological features in common with 'N. limicola' III and which have been presumed historically to be the same or very similar bacteria.

Liu JR ，McKenzie CA ，Seviour EM ，Webb RI ，Blackall LL ，Saint CP ，Seviour RJ ... -  《international journal of systematic and evolutionary microbiology》

Phylogenetic analysis and in situ identification of "Nostocoida limicola"-like filamentous bacteria in activated sludge from industrial wastewater treatment plants.

The diversity of filamentous bacteria present in industrial wastewater treatment plants was analysed by a combination of classical and molecular-biological approaches. Many unknown filamentous bacteria were observed in about 80 screened activated sludge samples from different industries with sometimes severe bulking sludge problems. A special focus was paid to filaments which resembled "Nostocoida limicola", a filamentous bacterium which was found to be present in many WWTPs. These filamentous bacteria are hardly cultivable and only one strain was obtained and maintained in co-culture with a yeast. The 16S rRNA sequences of several other "Nostocoida limicola"-like filamentous bacteria from different sludge samples were obtained by micromanipulation and different molecular-biological methods. The sequences were phylogenetically analyzed and specific molecular probes were developed and applied. The results clearly demonstrate that "Nostocoida limicola"-like filaments from industrial WWTPs are different from all other "Nostocoida limicola" types investigated so far. Our strains are affiliated to the alpha-subclass of Proteobacteria.

Snaidr I ，Beimfohr C ，Levantesi C ，Rossetti S ，van der Waarde J ，Geurkink B ，Elkelboom D ，Lemaitre M ，Tandoi V ... -  《WATER SCIENCE AND TECHNOLOGY》