THE USE OF SPECTROPHOTOMETRY IN AN ECOLOGICAL INVESTIGATION OF THE FACULTATIVELY ANAEROBIC PURPLE PHOTOSYNTHETIC BACTERIA

1967 ◽  
Vol 13 (9) ◽  
pp. 1283-1293 ◽  
Author(s):  
Edward F. Haskins ◽  
Toru Kihara
Keyword(s):  
Photosynthetic Bacteria ◽  
Rhodospirillum Rubrum ◽  
Rhodopseudomonas Palustris ◽  
Rhodopseudomonas Capsulata ◽  
Purple Photosynthetic Bacteria ◽  
Ecological Investigation ◽  
Facultatively Anaerobic ◽  
Isolation Techniques ◽  
Spectral Evidence ◽  
Rhodopseudomonas Spheroides

Diverse habitats were surveyed for the presence of Athiorhodaceae, using isolation techniques that permitted the development of only the facultatively anaerobic species of this family: Rhodopseudomonas capsulata, Rhodopseudomonas gelatinosa, Rhodopseudomonas palustris, Rhodopseudomonas spheroides, and Rhodospirillum rubrum. Of the 150 samples of soil, mud, sand, and water inoculated into enrichment media, 125 initiated cultures of photosynthetic bacteria, as indicated by spectrophotometric examination of the cultures. Subsequently, eight of these cultures were intensively investigated and isolates of the four species of Rhodopseudomonas were identified. Attempts to isolate Rhodospirillum rubrum from the cultures were unsuccessful. Species identifications were based on spectral examinations of aqueous cell-free preparations of the photosynthetic bacterial pigments. The species determinations based on the spectral evidence agreed with those based on the morphological and physiological criteria currently used for the identification of the Athiorhodaceae.

scholarly journals Changes in the acyl lipid composition of photosynthetic bacteria grown under photosynthetic and non-photosynthetic conditions

1979 ◽  
Vol 181 (2) ◽  
pp. 339-345 ◽  
Author(s):  
Nicholas J. Russell ◽  
John L. Harwood
Keyword(s):  
Fatty Acids ◽  
Photosynthetic Bacteria ◽  
Rhodospirillum Rubrum ◽  
Relative Proportion ◽  
Photosynthetic Apparatus ◽  
Growth Conditions ◽  
Rhodopseudomonas Capsulata ◽  
Rhodopseudomonas Sphaeroides ◽  
Acyl Lipids ◽  
And Function

The acyl lipids and their constituent fatty acids were studied in the photosynthetic bacteria Rhodospirillum rubrum, Rhodopseudomonas capsulata and Rhodopseudomonas sphaeroides, which were grown under photosynthetic and non-photosynthetic conditions. The major lipids were found to be phosphatidylethanolamine, phosphatidylglycerol and cardiolipin in each bacterium. The two Rhodopseudomonas species also contained significant quantities of phosphatidylcholine. Other acyl lipids accounted for less than 10% of the total. On changing growth conditions from non-photosynthetic to photosynthetic a large increase in the relative proportion of phosphatidylglycerol was seen at the expense of phosphatidyl-ethanolamine. In Rhodospirillum rubrum the fatty acids of the major phospholipids showed an increase in the proportion of palmitate and stearate and a decrease in palmitoleate and vaccenate on changing growth conditions to photosynthetic. In contrast, the exceptionally high levels (>80%) of vaccenate in individual phospholipids of Rhodopseudomonas capsulata and Rhodopseudomonas sphaeroides were unaffected by changing growth conditions to photosynthetic. Analysis of the lipids of chromatophores, isolated from the three bacteria, showed that these preparations were enriched in phosphatidylglycerol. The large increase in this phospholipid, seen during growth under photosynthetic conditions, appeared, therefore, to be due to a proliferation of chromatophore membranes. Possible roles for acyl lipids in the formation and function of the photosynthetic apparatus of bacteria are discussed.

scholarly journals Redirection of Metabolism for Biological Hydrogen Production

2007 ◽  
Vol 73 (5) ◽  
pp. 1665-1671 ◽  
Author(s):  
Federico E. Rey ◽  
Erin K. Heiniger ◽  
Caroline S. Harwood
Keyword(s):  
Nitrogen Fixation ◽  
Hydrogen Production ◽  
Photosynthetic Bacteria ◽  
Rhodopseudomonas Palustris ◽  
Photosynthetic Bacterium ◽  
Selection Strategy ◽  
Wild Type ◽  
Purple Photosynthetic Bacteria ◽  
Mutant Strains ◽  
Different Strains

ABSTRACT A major route for hydrogen production by purple photosynthetic bacteria is biological nitrogen fixation. Nitrogenases reduce atmospheric nitrogen to ammonia with the concomitant obligate production of molecular hydrogen. However, hydrogen production in the context of nitrogen fixation is a rather inefficient process because about 75% of the reductant consumed by the nitrogenase is used to generate ammonia. In this study we describe a selection strategy to isolate strains of purple photosynthetic bacteria in which hydrogen production is necessary for growth and independent of nitrogen fixation. We obtained four mutant strains of the photosynthetic bacterium Rhodopseudomonas palustris that produce hydrogen constitutively, even in the presence of ammonium, a condition where wild-type cells do not accumulate detectable amounts of hydrogen. Some of these strains produced up to five times more hydrogen than did wild-type cells growing under nitrogen-fixing conditions. Transcriptome analyses of the hydrogen-producing mutant strains revealed that in addition to the nitrogenase genes, 18 other genes are potentially required to produce hydrogen. The mutations that caused constitutive hydrogen production mapped to four different sites in the NifA transcriptional regulator in the four different strains. The strategy presented here can be applied to the large number of diverse species of anoxygenic photosynthetic bacteria that are known to exist in nature to identify strains for which there are fitness incentives to produce hydrogen.

Multiple-variant design for the enrichment of photosynthetic bacterial populations

1975 ◽  
Vol 21 (7) ◽  
pp. 1046-1054
Author(s):  
Thomas W. Jeffries ◽  
Richard G. Butler
Keyword(s):  
Liquid Culture ◽  
Photosynthetic Bacteria ◽  
Coliform Bacteria ◽  
Rhodopseudomonas Capsulata ◽  
Solid Culture ◽  
Bacterial Populations ◽  
Sulfate Reducing ◽  
Rhodopseudomonas Spheroides ◽  
Selection Of ◽  
Simultaneous Variation

A design for the simultaneous variation of acetate, sulfide, and sulfate concentrations in 11 related media is described. Selectivity of these media by a direct enumeration technique in solid culture was compared with that for enrichment in liquid culture. Variation of nutritional parameters resulted in the selection of Rhodospirillaceae at initial enrichment concentrations of 0.1 g or less of Na2S∙9 H2O per litre and Chromatiaceae at 0.1 to 1.0 g of Na2S∙9 H2O per litre. The survival of sulfate-reducing and coliform bacteria indicated interdependency of photosynthetic populations with the former and competition with the latter. Photosynthetic bacteria selectively cultivated in liquid enrichment were tentatively identified as Rhodopseudomonas capsulata, Rhodopseudomonas spheroides, Chromatium warmingii, Chromatium okenii, Thiospirillum, and Rhabdomonas.

Sign in / Sign up

Export Citation Format

Share Document