The phylogeny of purple bacteria: the alpha subdivision.

A phylogenetic definition of the major eubacterial taxa.

Structure, biosynthesis, and physicochemical properties of archaebacterial lipids.

Methanosaeta concilii gen. nov., sp. nov. (“Methanothrix concilii”) is described. Cells of species in the genus Methanosaeta are obligately anaerobic, gram-negative, nonmotile rods (length, 2.5 to 6.0 μm) with flat ends. The cells are enclosed within a proteinaceous, cross-striated sheath. Growth can occur as long filaments which represent chains of individual cells separated by spacer plugs and continuously enclosed by the tubular sheath. Acetic acid is used as the sole source of energy; its metabolism results in the production of about equimolar amounts of CH4 and CO2. Acetic acid and CO2 are carbon sources for growth. The description of Methanosaeta concilii, the type species, is based on type strain GP6 (= DSM 3671 = OGC 69 = NRC 2989 = ATCC 35969).

Methanosaeta concilii gen. nov. sp. nov. ("Methanothrix concilii") and Methanosaeta thermoacetophila nom. rev., comb. nov.?

A 16S ribosomal RNA gene has been sequenced from Heliobacterium chlorum, the recently discovered photosynthetic bacterium that contains a novel form of chlorophyll. Comparisons with other 16S ribosomal RNA sequences show that the organism belongs to the Gram-positive bacteria (one of ten eubacterial "phyla")--more precisely to the so-called low G + C (G, guanine; C, cytosine) subdivision thereof. This brings to five the number of such phyla that contain photosynthetic species, the other four being the purple bacteria and relatives, the green sulfur bacteria, the green nonsulfur bacteria, and the cyanobacteria. The finding suggests that Gram-positive bacteria may be of photosynthetic ancestry, and it strengthens the case for a common photosynthetic ancestry for all eubacteria.

https://science.sciencemag.org/content/sci/229/4715/762.full.pdf

Beat A. Huser

Papers

The Phylogenetic Position of Methanothrix soehngenii. Elucidated by a Modified Technique of Sequencing Oligonucleotides from 16S rRNA