Abstract
The roles of oxygen and light on the regulation of photosynthesis gene expression in Rhodobacter sphaeroides 2.4.1 have been well studied over the past 50 years. More recently, the effects of oxygen and light on gene regulation have been shown to involve the interacting redox chains present in R. sphaeroides under diverse growth conditions, and many of the redox carriers comprising these chains have been well studied. However, the expression patterns of those genes encoding these redox carriers, under aerobic and anaerobic photosynthetic growth, have been less well studied. Here, we provide a transcriptional analysis of many of the genes comprising the photosynthesis lifestyle, including genes corresponding to many of the known regulatory elements controlling the response of this organism to oxygen and light. The observed patterns of gene expression are evaluated and discussed in light of our knowledge of the physiology of R. sphaeroides under aerobic and photosynthetic growth conditions. Finally, this analysis has enabled to us go beyond the traditional patterns of gene expression associated with the photosynthesis lifestyle and to consider, for the first time, the full complement of genes responding to oxygen, and variations in light intensity when growing photosynthetically. The data provided here should be considered as a first step in enabling one to model electron flow in R. sphaeroides 2.4.1.
Highlights
The roles of oxygen and light on the regulation of photosynthesis gene expression in Rhodobacter sphaeroides 2.4.1 have been well studied over the past 50 years
The observed patterns of gene expression are evaluated and discussed in light of our knowledge of the physiology of R. sphaeroides under aerobic and photosynthetic growth conditions. This analysis has enabled to us go beyond the traditional patterns of gene expression associated with the photosynthesis lifestyle and to consider, for the first time, the full complement of genes responding to oxygen, and variations in light intensity when growing photosynthetically
In the present work we have extended our studies of oxygen control of gene expression as well as the role of high (100 W/m2) versus low (3 W/m2) light intensity on gene expression in R. sphaeroides 2.4.1
Summary
R. sphaeroides Growth Conditions—R. sphaeroides strains were grown at 30 Ϯ 0.5 °C on Sistrom’s minimal medium A containing. Photosynthetic cultures were grown at a light intensity of either 3 or 100 W/m2 measured at the surface of the growth vessel and sparging with 95% N2, 5% CO2 and harvested at A600 nm of 0.45 Ϯ 0.05, which insures that self-shading is not problem. Each isolated RNA sample was treated with 50 l of RQ1 RNase-free DNase (1 unit/l, Promega) and 50 l of 10ϫ buffer in a total volume of 500 l. Total RNA was pelleted again by adding the same volume of 4 M LiCl, washed with 75% ethanol, and resuspended in diethylpyrocarbonate-treated water. Intergenic regions are designated for DNA regions larger than 0.5 kb situated between ORFs. Almost 75% of these are shown to be actual ORFs. Total RNA was prepared from three independent cultures involving R. sphaeroides 2.4.1 grown under aerobic or photosynthetic conditions. The manuscript describing construction of the Affymetrix GeneChip will be published elsewhere
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
