Establishment of an unfed strain of and analysis of associated bacterial communities controlling its proliferation.

The ciliate harbors several hundred symbiotic algae in its cell and is widely used as an experimental model for studying symbiosis between eukaryotic cells. Currently, various types of bacteria and eukaryotic microorganisms are used as food for culturing ; thus, the cultivation conditions are not uniform among researchers. To unify cultivation conditions, we established cloned, unfed strains that can be cultured using only sterile medium without exogenous food.

Photosynthetic Growth and Energy Conversion in an Engineered Phototroph Containing Light-Harvesting Complex 1 and the Reaction Center Complex.

Light-harvesting complex 1 (LH1) of the thermophilic purple sulfur bacterium can be expressed in the purple non-sulfur bacterium and forms a functional RC-LH1 complex with the native reaction center (Nagashima, K. V. P.

Rubredoxin from the green sulfur bacterium Chlorobaculum tepidum donates a redox equivalent to the flavodiiron protein in an NAD(P)H dependent manner via ferredoxin-NAD(P) oxidoreductase.

The green sulfur bacterium, Chlorobaculum tepidum, is an anaerobic photoautotroph that performs anoxygenic photosynthesis. Although genes encoding rubredoxin (Rd) and a putative flavodiiron protein (FDP) were reported in the genome, a gene encoding putative NADH-Rd oxidoreductase is not identified. In this work, we expressed and purified the recombinant Rd and FDP and confirmed dioxygen reductase activity in the presence of ferredoxin-NAD(P) oxidoreductase (FNR).

Correction: Sakurai, H.; et al. How Close We Are to Achieving Commercially Viable Large-Scale Photobiological Hydrogen Production by Cyanobacteria: A Review of the Biological Aspects. Life 2015, 5, 997⁻1018.

In the published article "How close we are to achieving commercially viable large-scale photobiological hydrogen production by cyanobacteria:[...

Kinetics of NADP/NADPH reduction-oxidation catalyzed by the ferredoxin-NAD(P) reductase from the green sulfur bacterium Chlorobaculum tepidum.

Ferredoxin-NAD(P) oxidoreductase (FNR, [EC 1.18.1.

Genetic engineering of cyanobacteria to enhance biohydrogen production from sunlight and water.

To mitigate global warming caused by burning fossil fuels, a renewable energy source available in large quantity is urgently required. We are proposing large-scale photobiological H(2) production by mariculture-raised cyanobacteria where the microbes capture part of the huge amount of solar energy received on earth's surface and use water as the source of electrons to reduce protons. The H(2) production system is based on photosynthetic and nitrogenase activities of cyanobacteria, using uptake hydrogenase mutants that can accumulate H(2) for extended periods even in the presence of evolved O(2).

Flexible plastic bioreactors for photobiological hydrogen production by hydrogenase-deficient cyanobacteria.

Uptake hydrogenase mutant cells of the cyanobacterium Nostoc sp. PCC 7422 photobiologically produced H(2) catalyzed by nitrogenase for several days in H(2)-barrier transparent plastic bags, and accumulated H(2) in the presence of O(2) evolved by photosynthesis. Their H(2) production activity was higher in the sealed flexible bags than in stoppered serum bottles of fixed gas volume.

A feasibility study of large-scale photobiological hydrogen production utilizing mariculture-raised cyanobacteria.

In order to decrease CO(2) emissions from the burning of fossil fuels, the development of new renewable energy sources sufficiently large in quantity is essential. To meet this need, we propose large-scale H(2) production on the sea surface utilizing cyanobacteria. Although many of the relevant technologies are in the early stage of development, this chapter briefly examines the feasibility of such H(2) production, in order to illustrate that under certain conditions large-scale photobiological H(2) production can be viable.

NB-protein (BchN-BchB) of dark-operative protochlorophyllide reductase is the catalytic component containing oxygen-tolerant Fe-S clusters.

Dark-operative protochlorophyllide (Pchlide) oxidoreductase is a nitrogenase-like enzyme consisting of the two components, L-protein (BchL-dimer) and NB-protein (BchN-BchB-heterotetramer). Here, we show that NB-protein is the catalytic component with Fe-S clusters. NB-protein purified from Rhodobacter capsulatus bound Pchlide that was readily converted to chlorophyllide a upon the addition of L-protein and Mg-ATP.

Nitrogenase Fe protein-like Fe-S cluster is conserved in L-protein (BchL) of dark-operative protochlorophyllide reductase from Rhodobacter capsulatus.

Dark-operative protochlorophyllide reductase (DPOR) in bacteriochlorophyll biosynthesis is a nitrogenase-like enzyme consisting of L-protein (BchL-dimer) as a reductase component and NB-protein (BchN-BchB-heterotetramer) as a catalytic component. Metallocenters of DPOR have not been identified. Here we report that L-protein has an oxygen-sensitive [4Fe-4S] cluster similar to nitrogenase Fe protein.