Interplay between photosynthetic electron flux and organic carbon sinks in sucrose-excreting Synechocystis sp. PCC 6803 revealed by omics approaches.

Background: Advancing the engineering of photosynthesis-based prokaryotic cell factories is important for sustainable chemical production and requires a deep understanding of the interplay between bioenergetic and metabolic pathways. Rearrangements in photosynthetic electron flow to increase the efficient use of the light energy for carbon fixation must be balanced with a strong carbon sink to avoid photoinhibition. In the cyanobacterium Synechocystis sp.

Engineering RNA polymerase to construct biotechnological host strains of cyanobacteria.

Application of cyanobacteria for bioproduction, bioremediation and biotransformation is being increasingly explored. Photoautotrophs are carbon-negative by default, offering a direct pathway to reducing emissions in production systems. More robust and versatile host strains are needed for constructing production strains that would function as efficient and carbon-neutral cyanofactories.

Photosynthetically produced sucrose by immobilized Synechocystis sp. PCC 6803 drives biotransformation in E. coli.

Background: Whole-cell biotransformation is a promising emerging technology for the production of chemicals. When using heterotrophic organisms such as E. coli and yeast as biocatalysts, the dependence on organic carbon source impairs the sustainability and economic viability of the process.

A Plasmid-Based Fluorescence Reporter System for Monitoring Oxidative Damage in .

Quantitating intracellular oxidative damage caused by reactive oxygen species (ROS) is of interest in many fields of biological research. The current systems primarily rely on supplemented oxygen-sensitive substrates that penetrate the target cells, and react with ROS to produce signals that can be monitored with spectroscopic or imaging techniques. The objective here was to design a new non-invasive analytical strategy for measuring ROS-induced damage inside living cells by taking advantage of the native redox sensor system of .

Hydrocarbon Desaturation in Cyanobacterial Thylakoid Membranes Is Linked With Acclimation to Suboptimal Growth Temperatures.

The ability to produce medium chain length aliphatic hydrocarbons is strictly conserved in all photosynthetic cyanobacteria, but the molecular function and biological significance of these compounds still remain poorly understood. This study gives a detailed view to the changes in intracellular hydrocarbon chain saturation in response to different growth temperatures and osmotic stress, and the associated physiological effects in the model cyanobacterium sp. PCC 6803.

Comparison of alternative integration sites in the chromosome and the native plasmids of the cyanobacterium Synechocystis sp. PCC 6803 in respect to expression efficiency and copy number.

Background: Synechocystis sp. PCC 6803 provides a well-established reference point to cyanobacterial metabolic engineering as part of basic photosynthesis research, as well as in the development of next-generation biotechnological production systems. This study focused on expanding the current knowledge on genomic integration of expression constructs in Synechocystis, targeting a range of novel sites in the chromosome and in the native plasmids, together with established loci used in literature.

Photoautotrophic production of renewable ethylene by engineered cyanobacteria: Steering the cell metabolism towards biotechnological use.

Ethylene is a volatile hydrocarbon with a massive global market in the plastic industry. The ethylene now used for commercial applications is produced exclusively from nonrenewable petroleum sources, while competitive biotechnological production systems do not yet exist. This review focuses on the currently developed photoautotrophic bioproduction strategies that enable direct solar-driven conversion of CO into ethylene, based on the use of genetically engineered photosynthetic cyanobacteria expressing heterologous ethylene forming enzyme (EFE) from Pseudomonas syringae.

Redirecting photosynthetic electron flux in the cyanobacterium Synechocystis sp. PCC 6803 by the deletion of flavodiiron protein Flv3.

Background: Oxygen-evolving photoautotrophic organisms, like cyanobacteria, protect their photosynthetic machinery by a number of regulatory mechanisms, including alternative electron transfer pathways. Despite the importance in modulating the electron flux distribution between the photosystems, alternative electron transfer routes may compete with the solar-driven production of CO-derived target chemicals in biotechnological systems under development. This work focused on engineered cyanobacterial Synechocystis sp.

Enhanced stable production of ethylene in photosynthetic cyanobacterium Synechococcus elongatus PCC 7942.

Ethylene is a volatile alkene which is used in large commercial scale as a precursor in plastic industry, and is currently derived from petroleum refinement. As an alternative production strategy, photoautotrophic cyanobacteria Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 have been previously evaluated as potential biotechnological hosts for producing ethylene directly from CO, by the over-expression of ethylene forming enzyme (efe) from Pseudomonas syringae.

Induction of antibacterial proteins and peptides in the coprophilous mushroom Coprinopsis cinerea in response to bacteria.

Bacteria are the main nutritional competitors of saprophytic fungi during colonization of their ecological niches. This competition involves the mutual secretion of antimicrobials that kill or inhibit the growth of the competitor. Over the last years it has been demonstrated that fungi respond to the presence of bacteria with changes of their transcriptome, but the significance of these changes with respect to competition for nutrients is not clear as functional proof of the antibacterial activity of the induced gene products is often lacking.

Comparison of ethanol tolerance between potential cyanobacterial production hosts.

Cyanobacteria are photosynthetic prokaryotes that have been extensively studied as potential autotrophic biotechnological hosts for the production of different carbon-based end-products directly from atmospheric CO. While commercially competitive applications do not yet exist, the production of ethanol in cyanobacteria is the most mature technology, endorsed by relatively high production yields and established status of ethanol in the global biofuel market. Within this concept, the aim here was to systematically compare ethanol tolerance of different commonly used cyanobacterial strains and substrains, in order to assess their relative potential for biotechnological production platforms.

Translation efficiency of heterologous proteins is significantly affected by the genetic context of RBS sequences in engineered cyanobacterium Synechocystis sp. PCC 6803.

Background: Photosynthetic cyanobacteria have been studied as potential host organisms for direct solar-driven production of different carbon-based chemicals from CO and water, as part of the development of sustainable future biotechnological applications. The engineering approaches, however, are still limited by the lack of comprehensive information on most optimal expression strategies and validated species-specific genetic elements which are essential for increasing the intricacy, predictability and efficiency of the systems. This study focused on the systematic evaluation of the key translational control elements, ribosome binding sites (RBS), in the cyanobacterial host Synechocystis sp.

Comparison of orthologous cyanobacterial aldehyde deformylating oxygenases in the production of volatile C3-C7 alkanes in engineered .

(ADO) is a unique enzyme found exclusively in photosynthetic cyanobacteria, which natively converts acyl aldehyde precursors into hydrocarbon products embedded in cellular lipid bilayers. This capacity has opened doors for potential biotechnological applications aiming at biological production of diesel-range alkanes and alkenes, which are compatible with the nonrenewable petroleum-derived end-products in current use. The development of production platforms, however, has been limited by the relative inefficiency of ADO enzyme, promoting research towards finding new strategies and information to be used for rational design of enhanced pathways for hydrocarbon over-expression.

Structural Insights into the Mode of Action of the Peptide Antibiotic Copsin.

Defensins make up a class of cysteine-rich antimicrobial peptides, expressed by virtually all eukaryotes as part of their innate immune response. Because of their unique mode of action and rapid killing of pathogenic microbes, defensins are considered promising alternatives to clinically applied antibiotics. Copsin is a defensin-like peptide, previously identified in the mushroom Coprinopsis cinerea.

SRM dataset of the proteome of inactivated iron-sulfur cluster biogenesis regulator SufR in sp. PCC 6803.

This article contains SRM proteomics data related to the research article entitled"Inactivation of iron-sulfur cluster biogenesis regulator SufR in sp. PCC 6803 induces unique iron-dependent protein-level responses" (L. Vuorijoki, A.

Inactivation of iron-sulfur cluster biogenesis regulator SufR in Synechocystis sp. PCC 6803 induces unique iron-dependent protein-level responses.

Background: Iron-sulfur (Fe-S) clusters are protein-bound cofactors associated with cellular electron transport and redox sensing, with multiple specific functions in oxygen-evolving photosynthetic cyanobacteria. The aim here was to elucidate protein-level effects of the transcriptional repressor SufR involved in the regulation of Fe-S cluster biogenesis in the cyanobacterium Synechocystis sp. PCC 6803.

The effect of enhanced acetate influx on Synechocystis sp. PCC 6803 metabolism.

Background: Acetate is a common microbial fermentative end-product, which can potentially be used as a supplementary carbon source to enhance the output of biotechnological production systems. This study focuses on the acetate metabolism of the photosynthetic cyanobacterium Synechocystis sp. PCC 6803 which is unable to grow on acetate as a sole carbon source but still can assimilate it via acetyl-CoA-derived metabolic intermediates.

Pyridine nucleotide transhydrogenase PntAB is essential for optimal growth and photosynthetic integrity under low-light mixotrophic conditions in Synechocystis sp. PCC 6803.

Pyridine nucleotide transhydrogenase (PntAB) is an integral membrane protein complex participating in the regulation of NAD(P) :NAD(P)H redox homeostasis in various prokaryotic and eukaryotic organisms. In the present study we addressed the function and biological role of PntAB in oxygenic photosynthetic cyanobacteria capable of both autotrophic and heterotrophic growth, with support from structural three-dimensional (3D)-modeling. The pntA gene encoding the α subunit of heteromultimeric PntAB in Synechocystis sp.

Dual targeted poplar ferredoxin NADP(+) oxidoreductase interacts with hemoglobin 1.

Previous reports have connected non-symbiotic and truncated hemoglobins (Hbs) to metabolism of nitric oxide (NO), an important signalling molecule involved in wood formation. We have studied the capability of poplar (Populus tremula × tremuloides) Hbs PttHb1 and PttTrHb proteins alone or with a flavin-protein reductase to relieve NO cytotoxicity in living cells. Complementation tests in a Hb-deficient, NO-sensitive yeast (Saccharomyces cerevisiae) Δyhb1 mutant showed that neither PttHb1 nor PttTrHb alone protected cells against NO.

Development of a Quantitative SRM-Based Proteomics Method to Study Iron Metabolism of Synechocystis sp. PCC 6803.

The cyanobacterium Synechocystis sp. PCC 6803 (S. 6803) is a well-established model species in oxygenic photosynthesis research and a potential host for biotechnological applications.

A microbial platform for renewable propane synthesis based on a fermentative butanol pathway.

Background: Propane (C3H8) is a volatile hydrocarbon with highly favourable physicochemical properties as a fuel, in addition to existing global markets and infrastructure for storage, distribution and utilization in a wide range of applications. Consequently, propane is an attractive target product in research aimed at developing new renewable alternatives to complement currently used petroleum-derived fuels. This study focuses on the construction and evaluation of alternative microbial biosynthetic pathways for the production of renewable propane.

Copsin, a novel peptide-based fungal antibiotic interfering with the peptidoglycan synthesis.

Fungi and bacteria compete with an arsenal of secreted molecules for their ecological niche. This repertoire represents a rich and inexhaustible source for antibiotics and fungicides. Antimicrobial peptides are an emerging class of fungal defense molecules that are promising candidates for pharmaceutical applications.

An engineered pathway for the biosynthesis of renewable propane.

The deployment of next-generation renewable biofuels can be enhanced by improving their compatibility with the current infrastructure for transportation, storage and utilization. Propane, the bulk component of liquid petroleum gas, is an appealing target as it already has a global market. In addition, it is a gas under standard conditions, but can easily be liquefied.

Probing bacterial-fungal interactions at the single cell level.

Interactions between fungi and prokaryotes are abundant in many ecological systems. A wide variety of biomolecules regulate such interactions and many of them have found medicinal or biotechnological applications. However, studying a fungal-bacterial system at a cellular level is technically challenging.

A synthetic O2 -tolerant butanol pathway exploiting native fatty acid biosynthesis in Escherichia coli.

Several synthetic metabolic pathways for butanol synthesis have been reported in Escherichia coli by modification of the native CoA-dependent pathway from selected Clostridium species. These pathways are all dependent on the O2 -sensitive AdhE2 enzyme from Clostridium acetobutylicum that catalyzes the sequential reduction of both butyryl-CoA and butyraldehyde. We constructed an O2 -tolerant butanol pathway based on the activities of an ACP-thioesterase, acting on butyryl-ACP in the native fatty acid biosynthesis pathway, and a promiscuous carboxylic acid reductase.