Composite fluorescence micrograph of the *Candidatus" Bipolaricaulis cells, hybridized with the OP1-702 FISH probe (Cy3, red), and stained with Syto9 (green). Yellow signal indicates overlap of fluorescence from Cy3 and Syto9. Arrows indicate three slightly different morphologies: M1= central rod with bipolar prosthecae of similar length; M2= smaller central rod with bipolar prosthecae of different lengths; M3= smallest central rod with a single polar prostheca. An M1 cell which seems to be undergoing cell division is indicated with an asterisk. Scale bar represents 10 μm. - Source:1Fermentation
Novel genus belongs to phylum Candidatus Bipolaricaulota, formerly Candidatus Acetothermus. Single rod-shaped cells (~ 0.8 x 1~2 µm) with appendages (~ 0.4 x 4~8 µm) at both poles of the rod-shaped cell. Stably present in several mesophilic sludge digesters 1. Genomic reconstruction revealed a strictly anaerobic metabolism and fermentative physiology. Suggested to be involved in acidogenesis, producing organic acids (such as acetate and formate) and hydrogen from the fermentation of peptides, amino acids, and simple sugars (maltose, sucrose) 1.
OP1-702, OP1-838. Both probes cover all near full-length sequences of the proposed genus 1. The OP1-702 probe requires the helper probe OP1-702H1, and the inclusion of the OP1-838H2 probe for OP1-838 gives a noticeable increase in signal and is therefore recommended. The OP1-702 had superior signal to the OP1-838 probe, and it is recommended applying them both with different fluorochromes for increased confidence in their specificity 1.
 Hao, McIlroy, Kirkegaard, Karst, Fernando, Aslan, et al. - Novel prosthecate bacteria from the candidate phylum Acetothermia. - ISME J 12(9): 2225-2237. doi:10.1038/s41396-018-0187-9