Type

Journal Article

Authors

Kevin E O'Connor
Alexander Steinbüchel
Daniel Heinrich
Matthias Raberg
Cormac Murphy
Kieran Wynne
Gerard Cagney
Lorraine Brennan
Eibhlin Carr
Helena Gibbons
and 3 others

Subjects

Physiotherapy & Sport

Topics
rubisco activity ribulose bisphosphate carboxylase cell survival redox potential stress response roles aerobic physiological

Understanding the physiological roles of polyhydroxybutyrate (PHB) in Rhodospirillum rubrum S1 under aerobic chemoheterotrophic conditions. (2016)

Abstract Polyhydroxybutyrate (PHB) is an important biopolymer accumulated by bacteria and associated with cell survival and stress response. Here, we make two surprising findings in the PHB-accumulating species Rhodospirillum rubrum S1. We first show that the presence of PHB promotes the increased assimilation of acetate preferentially into biomass rather than PHB. When R. rubrum is supplied with (13)C-acetate as a PHB precursor, 83.5 % of the carbon in PHB comes from acetate. However, only 15 % of the acetate ends up in PHB with the remainder assimilated as bacterial biomass. The PHB-negative mutant of R. rubrum assimilates 2-fold less acetate into biomass compared to the wild-type strain. Acetate assimilation proceeds via the ethylmalonyl-CoA pathway with (R)-3-hydroxybutyrate as a common intermediate with the PHB pathway. Secondly, we show that R. rubrum cells accumulating PHB have reduced ribulose 1,5-bisphosphate carboxylase (RuBisCO) activity. RuBisCO activity reduces 5-fold over a 36-h period after the onset of PHB. In contrast, a PHB-negative mutant maintains the same level of RuBisCO activity over the growth period. Since RuBisCO controls the redox potential in R. rubrum, PHB likely replaces RuBisCO in this role. R. rubrum is the first bacterium found to express RuBisCO under aerobic chemoheterotrophic conditions.
Collections Ireland -> University College Dublin -> PubMed

Full list of authors on original publication

Kevin E O'Connor, Alexander Steinbüchel, Daniel Heinrich, Matthias Raberg, Cormac Murphy, Kieran Wynne, Gerard Cagney, Lorraine Brennan, Eibhlin Carr, Helena Gibbons and 3 others

Experts in our system

1
Kevin E O'Connor
University College Dublin
Total Publications: 52
 
2
Cormac D. Murphy
University College Dublin
Total Publications: 74
 
3
Kieran Wynne
Royal College of Surgeons in Ireland
Total Publications: 45
 
4
Gerard Cagney
Royal College of Surgeons in Ireland
Total Publications: 54
 
5
Lorraine Brennan
University College Dublin
Total Publications: 166
 
6
Eibhlin Carr
Trinity College Dublin
Total Publications: 3
 
7
Helena Gibbons
University College Dublin