This paper describes some new characteristics of the phosphoenolpyruvate carboxykinase CO(2)-oxaloacetate exchange reaction in purified preparations of Rhodospirillum rubrum. The enzymatic activity has been purified 169-fold. Nucleotide diphosphates substitute for nucleotide triphosphates in the exchange reaction. Nucleotide diphosphates will not support the synthesis of phosphoenolpyruvate fro...

An attempt was made to localize a number of O-methyl sugars in lipopolysaccharides and antigenic polysaccharides isolated from photosynthetic bacteria and from cyano-bacteria. Methylation analysis with [2H3]methyl iodide as methylating agent was the method of choice. One has to differentiate between (lipo-)polysaccharides having only trace amounts (less than 1% of polymer dry weight) of O-methy...

Two-dimensional electronic spectroscopy of Light Harvesting Complex 4 from photosynthetic bacteria reveals excited state dynamics on two timescales and resolves exciton states with little to no oscillator strength. The results suggest a molecular structure in which the pigment dipole organization within the circular complex has more tangential than radial character.

Several groups of chlorophyll-bearing photosynthetic organisms often coexist in anoxic waters. Because of the close similarity between the absorbance spectra of chlorophyll a (in cyanobacteria and algae) and the chlorophylls of green sulfur bacteria (Chl-GSB) it is difficult to distinguish these two groups of organisms where they co-occur. We have developed a simple method to measure both chlor...

Biohydrogen production technology is an emerging field for the advanced wastewater treatment with cogeneration of energy. Besides, hydrogen is an excellent candidate with high energy value (122 kJ/g) than other known carbon‐based fuels with no adverse effects to the environment as it releases only water vapor as the by‐products during the combustion. Biohydrogen production technology can be ass...

The important factor is the sequence of merging in symbiogenesis, i.e. the serial evolution. The first merger involved (1) thermoplasmic archaebacteria with motile spirochaeta-like eubacteria that (2) were able to swim, to the nucleocytoplasm. These forms were still anaerobic. This was followed by a merging with (3) aerobic organisms. This enabled them to survive the increasing oxygen concentra...

Enrichment cultures for purple nonsulfur and sulfur photosynthetic bacteria were prepared from soil samples collected in central and northern Minnesota. The purple nonsulfur bacteria were found in most wetland soils sampled but were uncommon in woodland and grassland soils. The pH range of the soils in which these bacteria occurred was 3.8 to 7.8, and the oxidation-reduction potential (E(h)) ra...

The relationship of the anaerobic, photoheterotrophic bacterium Rhodomicrobium vannielii to other photosynthetic bacteria is difficult to assess in view of its complex morphological characteristics (Duchow and Douglas, J. Bacteriol. 58: 409, 1949). A detailed examination of its carotenoid constitution was carried out to establish more clearly its relationship to other photosynthetic bacteria. A...

Selected examples of novel types of carotenoids studied in the author's laboratory during the past three years are discussed; including structural elucidation, total synthesis and biosynthetic considerations. Carotenoids of photosynthetic bacteria, particularly the aryl ketone okenone and cross-conjugated carotenals of the rhodopinal series, C50carotenoids of non-photosynthetic bacteria like de...

Recent experiments have revealed that the light-harvesting complex 1 (LH1) in purple photosynthetic bacteria has an elliptical structure. Generally, symmetry lowering in a structure leads to a decrease in quantum effects (quantum coherence and entanglement), which have recently been considered to play a role in photosynthetic energy transfer, and hence, elliptical structure seems to work agains...