Horizontal transfer of genes coding for the photosynthetic reaction centers of purple bacteria

Abstract

Phylogenetic trees were drawn and analyzed based on the nucleotide sequences of the 1.5-kb gene fragment coding for the L and M subunits of the photochemical reaction center of various purple photosynthetic bacteria. These trees are mostly consistent with phylogenetic trees based on 16S rRNA and soluble cytochrome c, but differ in some significant details. This inconsistency implies horizontal transfer of the genes that code for the photosynthetic apparatus in purple bacteria. Possibilities of similar transfers of photosynthesis genes during the evolution of photosynthesis are discussed especially for the establishment of oxygenic photosynthesis.

Effect of Bradyrhizobium photosynthesis on stem nodulation of Aeschynomene sensitiva

“…A similar conclusion has also been deduced previously on the basis of a 16S rDNA analysis (35). The congruence of these two approaches indicates that the photosynthetic character of strain ORS278 is not the result of a lateral transfer, as suggested for other photosynthetic bacteria (36), but rather evolved from a photosynthetic ancestor common to R. palustris. Most bradyrhizobia are root symbionts living in an environment devoid of light.…”

Unsuspected diversity among marine aerobic anoxygenic phototrophs

“…The pufM phylogenetic tree ( Fig. 1a) encompassed two principal clades, one containing a-3 and a-4 proteobacteria and one containing a-1, a-2, b-and g-proteobacteria representatives, in agreement with an earlier study 10 . The BAC clones fell into three groups on the basis of pufM gene phylogeny (Fig.…”

“…pufL and pufM ampli®cation Primers used in this study were pufL, forward (59-CTKTTCGACTTCTGGGTSGG-39) 10 ; pufM, reverse (59-CCATSGTCCAGCGCCAGAA-39) (a modi®cation of the primer reported by ref. 10); and pufM, forward (59-TACGGSAACCTGTWCTAC-39).…”

“…To better describe the nature and diversity of planktonic, anoxygenic, photosynthetic bacteria, we screened a surface-water bacterial arti®cial chromo- some (BAC) library 9 prepared from surface-water marine bacterioplankton, for clones containing pufL and pufM 10,11 genes. Several puf-containing BAC clones were identi®ed in screens using primers 10 designed to amplify almost the entire pufL and pufM region (1520±1580 nucleotides). In addition, several coastal a-proteobacterial strains previously isolated off the Oregon coast were also screened (R2A strains) 12 .…”

Involvement of the response regulator CtrA in the extracellular DNA production of the marine bacterium <i>Rhodovulum sulfidophilum</i>

“…Cultivation was performed essentially as described . The strains were grown anaerobically at 25∞C in a 1.5-ml or 50-ml tube filled with PYS medium (Nagashima et al, 1997) containing 2% (wt/ vol) NaCl under incandescent illumination (about 3,000 lux). Kanamycin was used at a concentration of 30 mg/ml for the strains containing the Kanamycin resistant gene.…”