Electron transport and light-harvesting switches in cyanobacteria

Work in this field in the author’s laboratory was funded by Biotechnology and Biological Sciences Research Council grants BB/G021856/1 and BB/J016985/1 and the European Commission through a Marie Curie Fellowship to Lu-Ning Liu (FP7-PEOPLE-2009-IEF254575) and the Marie Curie ITN Control of light-use efficiency in plants and algae – from light to harvest (HARVEST)

Bacteria in Solitary Confinement

Research in my laboratory is supported by Biotechnology and Biological Sciences Research Council grant BB/J016985/1

The influence of acetyl phosphate on DspA signalling in the Cyanobacterium Synechocystis sp PCC6803

<p>Abstract</p> <p>Background</p> <p>The <it>dspA </it>(<it>hik33</it>) gene, coding for a putative sensory histidine kinase, is conserved in plastids (<it>ycf26</it>) and cyanobacteria. It has been linked with a number of different stress responses in cyanobacteria.</p> <p>Results</p> <p>We constructed an insertional mutant of <it>dspA </it>(<it>ycf26) </it>in <it>Synechocystis </it>6803. We found little phenotypic effect during nitrogen starvation. However, when the mutation was combined with deletion of the <it>pta </it>gene coding for phosphotransacetylase, a more significant phenotype was observed. Under nitrogen starvation, the <it>pta/dspA </it>double mutant degrades its phycobilisomes less than the wild type and still has about half of its chlorophyll-protein complexes.</p> <p>Conclusion</p> <p>Our data indicates that acetyl-phosphate-dependent phosphorylation of response regulator(s) overlaps with DspA-dependent signalling of the degradation of chlorophyll-protein complexes (and to a lesser extent phycobilisomes) in <it>Synechocystis </it>6803.</p

Independent mobility of proteins and lipids in the plasma membrane of Escherichia coli

Biotechnology and Biological Sciences Research Council. Grant Number: BB/E009571, Oxford Centre for Integrative Systems Biology (OCISB), Engineering and Physical Science Research Council, Royal Society, Hertford College Oxfor

Specific Glucoside Transporters Influence Septal Structure and Function in the Filamentous, Heterocyst-Forming Cyanobacterium Anabaena sp Strain PCC 7120

T When deprived of combined nitrogen, some filamentous cyanobacteria contain two cell types: vegetative cells that fix CO2 through oxygenic photosynthesis and heterocysts that are specialized in N2 fixation. In the diazotrophic filament, the vegetative cells provide the heterocysts with reduced carbon (mainly in the form of sucrose) and heterocysts provide the vegetative cells with combined nitrogen. Septal junctions traverse peptidoglycan through structures known as nanopores and appear to mediate intercellular molecular transfer that can be traced with fluorescent markers, including the sucrose analog esculin (a coumarin glucoside) that is incorporated into the cells. Uptake of esculin by the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 was inhibited by the -glucosides sucrose and maltose. Analysis of Anabaena mutants identified components of three glucoside transporters that move esculin into the cells: GlsC (Alr4781) and GlsP (All0261) are an ATP-binding subunit and a permease subunit of two different ABC transporters, respectively, and HepP (All1711) is a major facilitator superfamily (MFS) protein that was shown previously to be involved in formation of the heterocyst envelope. Transfer of fluorescent markers (especially calcein) between vegetative cells of Anabaena was impaired by mutation of glucoside transporter genes. GlsP and HepP interact in bacterial two-hybrid assays with the septal junction-related protein SepJ, and GlsC was found to be necessary for the formation of a normal number of septal peptidoglycan nanopores and for normal subcellular localization of SepJ. Therefore, beyond their possible role in nutrient uptake in Anabaena, glucoside transporters influence the structure and function of septal junctions.Peer reviewe

Intercellular Diffusion of a Fluorescent Sucrose Analog via the Septal Junctions in a Filamentous Cyanobacterium

D.J.N. was supported by a Queen Mary University of London College studentship. M.N.M. was the recipient of an FPU (Formación del Personal Universitario) fellowship from the Spanish Government. Work in Seville was supported by grant BFU2011-22762 from Plan Nacional de Investigación, Spain, cofinanced by the European Regional Development Fund, and by Plan Andaluz de Investigación, Regional Government of Andalucía (grant P10-CVI-6665). Research in Tübingen was supported by the Deutsche Forschungsgemeinschaft (SFB766)

RNA-FISH as a probe for heterogeneity at the cellular and subcellular levels in cyanobacteria

The abundance and subcellular location of specific mRNA molecules can give rich information on bacterial cell biology and gene expression at the single-cell level. We have been using RNA Fluorescent in situ Hybridization (RNA-FISH) to probe for specific mRNA species in both unicellular and filamentous cyanobacteria. We have shown that the technique can be used to reveal the locations of membrane protein production and can also reveal heterogeneity in gene expression at the single-cell level, including patterns of gene expression within the filaments of heterocyst-forming cyanobacteria as they differentiate in diazotrophic conditions. However, the background fluorescence from pigments in cyanobacteria can cause problems, as can the resistance of heterocysts to permeabilization. Here we discuss the potential and the pitfalls of RNA-FISH as applied to cyanobacteria. We compare the information that can be obtained from RNA-FISH with that available from other techniques for probing gene expression.</jats:p

Solar powered biohydrogen production requires specific localization of the hydrogenase

This work was supported by BBSRC Grant (BB/G021856/1) to SJB, PJN and CWM. We acknowledge support from the U.S. DoE, Biological and Environmental Research Program to MB, the U.S. DoE Fuel Cell Technologies Office (contract number DE-AC36-08-GO28308) to CAE and EPSRC (EP/F00270X/1) to MB and PJN

Localisation and interactions of the Vipp1 protein in cyanobacteria

Biotechnology and Biological Sciences Research Council. Grant Number: BB/G021856. Deutsche Forschungsgemeinschaft. Grant Number: FOR 929, SCHN 690/3-1. European Commission. Grant Number: FP7-PEOPLE-2009-IEF 254575. NFR. Grant Numbers: 192436, 197119. OCISB. Royal Society and Engineering and Physical Sciences Research Council. Grant Number: EP/G0061009/