scholarly journals Genes Involved in the Biosynthesis of Photosynthetic Pigments in the Purple Sulfur Photosynthetic Bacterium Thiocapsa roseopersicina

2003 ◽  
Vol 69 (6) ◽  
pp. 3093-3102 ◽  
Author(s):  
�kos T. Kov�cs ◽  
G�bor R�khely ◽  
Korn�l L. Kov�cs
Keyword(s):  
Mutant Strain ◽  
Photosynthetic Bacteria ◽  
Photosynthetic Reaction Center ◽  
Photosynthetic Bacterium ◽  
Chromosomal Locus ◽  
Reading Frame ◽  
Purple Photosynthetic Bacteria ◽  
Thiocapsa Roseopersicina ◽  
Photosynthetic Genes ◽  
General Arrangement

ABSTRACT A pigment mutant strain of the purple sulfur photosynthetic bacterium Thiocapsa roseopersicina BBS was isolated by plasposon mutagenesis. Nineteen open reading frame, most of which are thought to be genes involved in the biosynthesis of carotenoids, bacteriochlorophyll, and the photosynthetic reaction center, were identified surrounding the plasposon in a 22-kb-long chromosomal locus. The general arrangement of the photosynthetic genes was similar to that in other purple photosynthetic bacteria; however, the locations of a few genes occurring in this region were unusual. Most of the gene products showed the highest similarity to the corresponding proteins in Rubrivivax gelatinosus. The plasposon was inserted into the crtD gene, likely inactivating crtC as well, and the carotenoid composition of the mutant strain corresponded to the aborted spirilloxanthin pathway. Homologous and heterologous complementation experiments indicated a conserved function of CrtC and CrtD in the purple photosynthetic bacteria. The crtDC and crtE genes were shown to be regulated by oxygen, and a role of CrtJ in aerobic repression was suggested.

scholarly journals Expression of Uptake Hydrogenase and Molybdenum Nitrogenase in Rhodobacter capsulatus Is Coregulated by the RegB-RegA Two-Component Regulatory System

2000 ◽  
Vol 182 (10) ◽  
pp. 2831-2837 ◽  
Author(s):  
Sylvie Elsen ◽  
Wanda Dischert ◽  
Annette Colbeau ◽  
Carl E. Bauer
Keyword(s):  
Photosynthetic Bacteria ◽  
Rhodobacter Capsulatus ◽  
Regulatory System ◽  
Photosynthetic Bacterium ◽  
Uptake Hydrogenase ◽  
Carbon And Nitrogen ◽  
Cellular Energy ◽  
Purple Photosynthetic Bacteria ◽  
Two Component

ABSTRACT Purple photosynthetic bacteria are capable of generating cellular energy from several sources, including photosynthesis, respiration, and H2 oxidation. Under nutrient-limiting conditions, cellular energy can be used to assimilate carbon and nitrogen. This study provides the first evidence of a molecular link for the coregulation of nitrogenase and hydrogenase biosynthesis in an anoxygenic photosynthetic bacterium. We demonstrated that molybdenum nitrogenase biosynthesis is under the control of the RegB-RegA two-component regulatory system in Rhodobacter capsulatus. Footprint analyses and in vivo transcription studies showed that RegA indirectly activates nitrogenase synthesis by binding to and activating the expression of nifA2, which encodes one of the two functional copies of the nif-specific transcriptional activator, NifA. Expression of nifA2 but notnifA1 is reduced in the reg mutants up to eightfold under derepressing conditions and is also reduced under repressing conditions. Thus, although NtrC is absolutely required fornifA2 expression, RegA acts as a coactivator ofnifA2. We also demonstrated that in regmutants, [NiFe]hydrogenase synthesis and activity are increased up to sixfold. RegA binds to the promoter of the hydrogenase gene operon and therefore directly represses its expression. Thus, the RegB-RegA system controls such diverse processes as energy-generating photosynthesis and H2 oxidation, as well as the energy-demanding processes of N2 fixation and CO2 assimilation.

scholarly journals Genome Sequence of the Unusual Purple Photosynthetic Bacterium Phaeovibrio sulfidiphilus, Only Distantly Related to Rhodospirillaceae, Reveals Unique Genes for Respiratory Nitrate Reduction and Glycerol Metabolism

2020 ◽  
Vol 9 (49) ◽  
Author(s):  
S. Dubey ◽  
T. E. Meyer ◽  
J. A. Kyndt
Keyword(s):  
Nitrate Reduction ◽  
Photosynthetic Bacteria ◽  
Photosynthetic Bacterium ◽  
Gene Clusters ◽  
Glycerol Metabolism ◽  
Freshwater Species ◽  
Content Type ◽  
Purple Photosynthetic Bacteria ◽  
Purple Photosynthetic Bacterium ◽  
Unique Genes

ABSTRACT Phaeovibrio sulfidiphilus was reported to be a divergent member of the purple photosynthetic bacteria with limited ability to metabolize organic compounds. Whole-genome-based analysis shows that it is indeed only distantly related to freshwater species of Rhodospirillaceae. Unexpectedly, the genome contains unique gene clusters for potential respiratory nitrate reduction and anaerobic glycerol metabolism.

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.

scholarly journals Peptide-Mediated Gene Transfer into Marine Purple Photosynthetic Bacteria

2020 ◽  
Vol 21 (22) ◽  
pp. 8625
Author(s):  
Mieko Higuchi-Takeuchi ◽  
Takaaki Miyamoto ◽  
Choon Pin Foong ◽  
Mami Goto ◽  
Kumiko Morisaki ◽  
...  
Keyword(s):  
Plasmid Dna ◽  
Photosynthetic Bacteria ◽  
Photosynthetic Bacterium ◽  
Dna Delivery ◽  
Transformation Method ◽  
Endosomal Escape ◽  
Purple Photosynthetic Bacteria ◽  
Rhodovulum Sulfidophilum ◽  
Wide Range ◽  
Plasmid Delivery

Use of photosynthetic organisms is one of the sustainable ways to produce high-value products. Marine purple photosynthetic bacteria are one of the research focuses as microbial production hosts. Genetic transformation is indispensable as a biotechnology technique. However, only conjugation has been determined to be an applicable method for the transformation of marine purple photosynthetic bacteria so far. In this study, for the first time, a dual peptide-based transformation method combining cell penetrating peptide (CPP), cationic peptide and Tat-derived peptide (dTat-Sar-EED) (containing D-amino acids of Tat and endosomal escape domain (EED) connected by sarcosine linkers) successfully delivered plasmid DNA into Rhodovulum sulfidophilum, a marine purple photosynthetic bacterium. The plasmid delivery efficiency was greatly improved by dTat-Sar-EED. The concentrations of dTat-Sar-EED, cell growth stage and recovery duration affected the efficiency of plasmid DNA delivery. The delivery was inhibited at 4 °C and by A22, which is an inhibitor of the actin homolog MreB. This suggests that the plasmid DNA delivery occurred via MreB-mediated energy dependent process. Additionally, this peptide-mediated delivery method was also applicable for E. coli cells. Thus, a wide range of bacteria could be genetically transformed by using this novel peptide-based transformation method.

Effects of algae, yeast and photosynthetic bacteria diets on survival and growth performance in the fairy shrimp, Streptocephalus sirindhornae (Branchiopoda, Anostraca)

Crustaceana ◽  
2018 ◽  
Vol 91 (12) ◽  
pp. 1505-1522 ◽  
Author(s):  
Chewapat Saejung ◽  
Anuwat Chaiyarat ◽  
La-Orsri Sanoamuang
Keyword(s):  
Growth Performance ◽  
Photosynthetic Bacteria ◽  
Photosynthetic Bacterium ◽  
Ammonia Concentration ◽  
Fairy Shrimp ◽  
Shrimp Culture ◽  
Survival And Growth ◽  
Nitrate And Nitrite ◽  
First Time

Abstract This study investigated the effects on survival, growth performance and water quality of algae, yeast and photosynthetic bacteria as diets for larval and immature/mature Streptocephalus sirindhornae. Survival of the larvae fed with the alga Chlorella vulgaris and the photosynthetic bacterium Rhodopseudomonas faecalis for 5 days was higher than 80%, while those fed with the yeast Saccharomyces cerevisiae was 4.4%. After feeding the 6-day-old fairy shrimp until they reached 30 days of age, those fed with bacteria showed the highest survival and growth rate. Ammonia, nitrate and nitrite concentrations in the water treated with R. faecalis were the lowest. The highest ammonia concentration, the lowest dissolved oxygen, and excessive turbidity were found in the yeast treatment. Frequent water replacement could not overcome this, which resulted in the low survival rate. Utilization of photosynthetic bacteria in fairy shrimp culture is for the first time reported herein, and the disadvantages of using yeast in S. sirindhornae cultivation are discussed.

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