Habitats of Phototrophic Prokaryotes

Bacteria of the Chloroflexus-subgroup form dense microbial mats in geothermal springs, often in close association with cyanobacteria. Chloroflexus aurantiacus is a thermophilic bacterium which grows optimally between 52 and 60 C and thrives in neutral to alkaline hot springs up to 70-72 C. Of all anoxygenic pho-totrophic bacteria isolated so far, only Chlorof- lexus aurantiacus is capable of growth up to 74 C. In contrast to the domain Archaea, no hyperthermophilic species are known from the...

Introduction

Photosynthesis is the utilization of radiant energy for the synthesis of complex organic molecules. The phototrophic way of life implies the capture of electromagnetic energy (see Light Absorption and Light Energy Transfer in Prokaryotes in this Chapter), its conversion into chemical energy (see Conversion of Light into Chemical Energy in this Chapter), and its use for cellular maintenance and growth (see Efficiency of Growth and Maintenance Energy Requirements in this Chapter). Photosynthesis...

Carbon Metabolism of Phototrophic Prokaryotes

In the natural environment, the principal carbon source of phototrophic bacteria in many instances is CO2 (Madigan et al., 1989 Sinninghe Damste et al., 1993 Takahashi et al., 1990). In Cyanobacteria, Chromatiaceae, Ectothiorho-dospiraceae and purple nonsulfur bacteria, CO2 is assimilated by the reductive pentose phosphate or Calvin cycle. Employing this cycle, the formation of one molecule of glyceraldehyde-3-phosphate requires 6 NAD(P)H+H+ and 9 ATP. By comparison, the reductive tricarboxylic...

Info

Bacteriochlorophyll g of the Heliobacteriaceae shows structural relationships to chlorophyll a because it contains a vinyl group on tetrapyrrole ring I. Like in bacteriochlorophylls a and b, pyrrole ring II is reduced, however, and the esterifying alcohol is famesol as in bacteriochlorophylls of green sulfur bacteria. As for bacteriochlorophyll a or b, the reduced state of ring II in bacteriochlorophyll g causes an additional though smaller absorption maximum, the Qx band at about 567nm. n.d.,...

The Prokaryotes

A Handbook on the Biology of Bacteria Volume 2 Ecophysiology and Biochemistry Martin Dworkin (Editor-in-Chief), Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer, Erko Stackebrandt (Editors) Editor-in-Chief Professor Dr. Martin Dworkin Department of Microbiology University of Minnesota Box 196 University of Minnesota Minneapolis, MN 55455-0312 USA Professor Dr. Stanley Falkow Department of Microbiology and Immunology Stanford University Medical School 299 Campus Drive, Fairchild D039...

Chloroflexaceae and Related Bacteria

10.1 The Family Chloroflexaceae 815 satoshi hanada and beverly k. pierson 10.2 The Genus Thermoleophilum 843 jerome j. perry 10.3 The Genus Thermomicrobium 849 jerome j. perry 10.4 The Genus Herpetosiphon 854 11.1 The Phylum Verrucomicrobia A Phylogenetically Heterogeneous heinz schlesner, cheryl jenkins and james t. staley

Mechanisms of Adhesion to Surfaces

Full details of proposed mechanisms of adhesion of prokaryotes to solid surfaces have been presented elsewhere (Marshall, 1985, 1986a) so only a brief outline will be presented in this paper. Water currents induced by temperature and gravity (fluid dynamic forces) provide the major mechanism for the transport of planktonic bacteria over large distances. When bacteria and other particles in flowing water are transported to the region of the boundary layer near a solid surface, a lift force...

Principles and Prerequisites of Photosynthesis

Bacterial photosynthesis can be divided into two different types of reactions 1) the light reaction, in which light energy is trapped and converted into ATP (via a proton-motive force DP) and a reduced redox carrier RredH+, and 2) the so-called dark reaction of biosynthetic carbon reduction. Light reaction 2H2A + 2Rox + light 2A + 2RredH + DP ADP + PI + DP ATP + H2O Dark reaction CO2 + ATP + 2RredH + H2O < CH2O> + ADP + Pi + 2Rox Sum CO2 + 2H2A < CH2O> + H2O + 2A (van Niel equation)...

Bacteroides and Cytophaga Group

6.1 The Medically Important Bacteroides spp. in Health and Disease 381 c. jeffrey smith, edson r. rocha and bruce j. paster 6.2 The Genus Porphyromonas 428 frank c. gibson and Caroline attardo genco 6.3 An Introduction to the Family Flavobacteriaceae 455 jean-fran ois bernardet and yasuyoshi nakagawa 6.4 The Genus Flavobacterium 481 jean-fran ois bernardet and john p. bowman 6.5 The Genera Bergeyella and Weeksella 532 celia j. hugo, brita bruun and piet j. jooste 6.6 The Genera Flavobacterium,...

Firmicutes with Atypical Cell Walls

1.3.1 The Family Heliobacteriaceae 951 michael t. madigan 1.3.2 Pectinatus, Megasphaera and Zymophilus 965 auli haikara and ilkka helander 1.3.3 The Genus Selenomonas 982 robert b. hespell, bruce j. paster and floyd e. dewhirst 1.3.4 The Genus Sporomusa 991 john a. breznak 1.3.5 The Family Lachnospiraceae, Including the Genera Butyrivibrio, Lachnospira and Roseburia 1002 michael cotta and robert forster 1.3.6 The Genus Veillonella 1022 paul kolenbrander martin sobierj and david r. boone

Light Absorption and Light Energy Transfer in Prokaryotes

The chlorophyll-based photosystems of bacteria convert electromagnetic energy into a redox gradient. The redox reactions are initiated by absorption of electromagnetic energy, leading to a transition of specific molecules into an excited electronic state. An increase in the electronic energy of a molecule requires more energy than changes in vibrational or rotational states. Since the energy of light quanta is inversely related to their wavelength (Planck's Law), molecules absorb...

Concluding Remarks

Experiments in animals have proven that it is possible to prevent infections by blocking the adhesion of the pathogen to target tissue. These findings have stimulated the development of anti-adhesion drugs for preventing and treating microbial infections in humans (reviewed in Kah-ane and Ofek, 1996). New classes of these drugs are greatly needed because of the increasing incidence of pathogenic organisms resistant to conventional antibiotics. It is believed that strains with genotypic...

Taxonomy of Phototrophic Prokaryotes

The capacity for chlorophyll-based photosyn-thetic energy conversion is found in five of the 36 currently recognized bacterial lineages Fig. 1 Hugenholtz et al., 1998 the Chloroflexus subgroup, the green sulfur bacteria, the Proteo-bacteria, the Cyanobacteria, and the Heliobacte-riaceae. With the exception of the Cyanobacteria, phototrophic bacteria perform anoxygenic photosynthesis, which is not accompanied by photochemical cleavage of water and therefore does not lead to the formation of...